anchovy and munida spatio-temporal dynamic and ... doccuments/2005/u/u2205.pdf · anchovy and...

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ICES CM 2005/U:22 Anchovy and munida spatio-temporal dynamic and interactions of diel cycles of aggregation Mariano Gutierrez(1), Francois Gerlotto(2), Luis Vasquez(1), Andres Chipollini(1)

_____________________________________________________________________________________ ABSTRACT The Northern Humboldt Current Ecosystem (NHCE) is mainly characterized by a predominance of pelagic species that have adapted to high variability on the hydrological conditions and frequent changes in the composition of plankton communities. Along the Peruvian coast anchovy (Engraulis ringens) is the most abundant fish whose general spatial patterns of distribution are known though details of its aggregative dynamic have rarely been described nor its relationships with the identity and local abundance of zooplankton. One of these zooplankton species is the likewise abundant munida (Pleuroncodes monodom) that is a crustacean not endemic to the northern region of the NHCE though its distribution greatly overlaps with anchovy. We hypothesize that presence of munida inhibits or modifies the aggregative dynamic of anchovy. To address these relationships an acoustic survey on behavioral ecology was performed during November 2004 over two small zones with different features. The survey was designed to determine interactions and diel patterns of aggregation and lasted 28 hours in each zone, and was followed up by trawling, biological samplings and oceanographic casts over the same time period. We produced 3D echograms to facilitate comparisons of echo traces and to determine analogies and differences between the zones. In the first zone (Pucusana) both anchovy and munida were recorded. The second zone was useful for comparative purposes because anchovy alone was detected. Among other aspects it was observed that formation of anchovy schools at dawn was faster in areas where munida was scarce or absent. Keywords: anchovy, munida, school, swarm, diel cycle, overlapping Contact author: Mariano Gutierrez: (1) Peruvian Marine Research Institute - IMARPE, e-mail: [email protected] (2) French Institute of Research for Development – IRD. _____________________________________________________________________________________ INTRODUCTION Within the northern region of the Humboldt Current Ecosystem (NHCE) it is anchovy (Engraulis ringens) the most important pelagic fish in terms of abundance and ecological significance (Clark, 1954; Schweigger, 1964; Boerema et al, 1965; Gulland, 1968; Jordan, 1971; Doe, 1978; Csirke, 1980; Pauly et al, 1986; Bertrand et al, 2004). However the species composition of the ecosystem presents variations that depend upon climatic conditions of medium duration such as El Niño or la Niña (Arntz & Fahrbach, 1996), or decadal cycles such as El Viejo or La Vieja (Chavez et al, 2003). It means that anchovy can not be predominant during certain periods, at is shown by the alternation between anchovy and sardine (Chavez et al, 2003; Bertrand et al, 2004; Alheit & Ñiquen, 2004; Espino, 2004; Gutiérrez et al, 2005). Altough it is not documented it might exist other type of alternation, or at least competition, among anchovy and a specie of anomorous crustacean known in Peru and Chile as munida or little red shrimp (Pleuroncodes monodom). This essentially coastal specie (Palma, 1994), that is endemic to the southern Humboldt Current Ecosystem (SHCE) and to the chilean marine ecosystem (Gallardo, 1992), is linked to the influence of sub-antantarctic waters (SAW; Bahamonde et al, 1979). Munida is secularly collected in the southern end of Peruvian coast though in rather small amounts as companion fauna of the pelagic fishery (Franco, 2003), then the larger supply of SAW in coastal upwelling linked to cold periods constitutes an ideal scope for the increase of its abundance (Gutiérrez et al, 2001; Franco, 2003).

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The population of munida was for first time acoustically assessed during summer of 1996 due to the observation of constant increase of its abundance since summer of 1994 along the south coast of Peru (Segura & Castillo, 1996). The acoustic monitoring performed between 1996 and 2004 has permitted to state that munida has enlarged its winter distribution towards the northern Peru (5°S) following up the flux of Coastal Cold Waters (CCW) that seems to have started after El Niño 1997-98 (Espino, 2003; Gutiérrez, 2005). This favorable cycle for munida must have happened in the past, as it is noted by studies of Del Solar (1942) cited by Scweiggger (1964), who describes that along the coastal zone from 4 to 17°S they were sampled stomachs of tunas and skip-jacks to found similar proportion of anchovy and munida within them. Schweigger (1964) proposed that munida might be part of the typical ecological nucleus of the NHCE together with anchoveta, the guano-producing bird guanay (Phalacrocórax bouganvillii) and the pelagic fish skip-jack or bonito (Sarda chilensis). In rather recent times, Elliott & Paredes (1997) observed individuals of munida in stomachs of hake (Merluccius gayi peruanus) and other species such as sharks, mackerel, jack-mackerel, cachema, catfish, anchovy etc. At the other hand, Arias-Schereiber (1996) revealed that munida constitutes around 75% of the diet of sea-lions in the zone of the Paracas Peninsula (14°S), and of sea birds in that area (Jahncke, 1997). Besides, the specie is being observed in water masses different than CCW, so it could be adapting to different conditions and even to northern regions than 5°S (L. Vásquez, pers. comm., 2005). Therefore if munida might be part of the main trophic path of the NHCE it is important to know its habits, what is the way it occupies space of the coastal marine ecosystem, and to know in which way munida interact with the other great inhabitant of coastal zones, the Peruvian anchovy. If a structured behavior exists it will only benefit that population (Parrish et al, 1997), then it is interesting to know at what extent this could be true in this case. In the same sense this knowledge might have implies in the possible existence of a bottom-up control in the NHCE if we consider the shortage of predators but mammals (E. Goya, pers. comm., 2004) and coastal fishes (C. Estrella, pers. comm., 2004) that is being observed in the ecosystem since 1997. To give a start to the study of these processes it was carried out a first survey on behavioral ecology during November 2004 between 12 and 14°S aboard RV Olaya of the Peruvian Marine Research Institute (IMARPE). From the collected data our work makes focus in one way anchovy and munida share coastal space (see figure 1), including aspects of the diel distribution, overlapping, relative abundance of zooplankton and oceanographic features, all of them analyzed in the context of indexes and volumes of acoustic backscattering (NASC, Sv).

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Figure 1. Distribution and relative NASC density of munida (right) and anchovy (center) along peruvian coastsduring winter 2004. The overlapping (at left side) of the two species in the coastal ecosystem is important(>70% of munida distribution) at least during winters of the 2000-2004 period).

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MATERIAL AND METHODS It was carried out a survey on behavioral ecology of pelagic species aboard RV Olaya during November 2004 along the central coast off Peru. For the acoustic surveying it was used a Simrad EK500 (firmware v.5.30) echosounder operating at 38 and 120 kHz (medium pulse length, wide bandwidth for both frequencies). The echosounder was previously calibrated according to what was described by MacLennan & Simmonds (1992). After a previous quick survey there were selected two study areas for comparative approach: the first was located at 8 n.mi. at south-west of Pucusana (12°30´S) on a mean depth of 118 m, in which there were acoustically detected anchovy, munida and zooplankton (mainly euphausiids); the second zone was located at 18 n.mi. at north-west of the Paracas Peninsula (13°50´S) on a mean depth of 182 m, in which it was detected anchovy and zooplankton (mainly euphausiids, once again). In every one of these zones it was performed a continuous acoustic swept at 8 knots speed around squares of 2 by 2 n.mi. 28 times over a period of 28 hours to ensure the covering of at least a complete diel cycle of the vertical distribution of the two species of main interest. See figure 2. During the acoustic survey it was continuously collected surface oceanographic information (temperature, CO2, among others). After completing the two series of 28 laps there were alternated oceanographic casts with fishing stations (mid-water trawling) during a diel cycle (24 hours) in order to identify targets and relate vertical distribution of studied species to vertical oceanic structure. It was used Echolog and Echoview software (SonarData Pty. Ltd.) for collecting and preliminary processing of the data. Of the collected data through out the echosounder they were chosen type ´W´ echograms of 38 and 120 kHz from 0 to 50 m depth, on which they were created virtual echograms to identify and separate the recordings attributed to different species taking advantage of the differences that it existed on their backscattering levels (Sv) for two frequencies (Greenlaw, 1983; Higgimbottom et al, 2000). The created algorithm permitted: to harmonize the two echograms regarding their dimensions and samples size; to subtract noise; to apply a filter where the difference between the echograms fitted within a range from 4 to 25 dB was attributed to anchovy echo-traces; to detect recordings of fish schools and swarms in order to obtain information on morphologic features using SHAPES algorithm of Echoview; to obtain indexes of relative abundance of zooplankton by arbitrarily removing values outside a threshold from –62 to –90 dB; and for creating separated echograms for every one of the studied species. Figure 3. There were built four types of databases: horizontal geographical and vertical location; parameters of acoustic density; geometric; and statistical. Furthermore, the generation of databases have been made under distinct criteria of division of the insonified space: by regions (sites occupied by fish schools, swarms or microgroups) and by cells (vertical rectangles of 0.25 n.mi. long by 2 m high, to analyze changes in vertical distribution in short periods of time).

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Figure 2. Location of the two studied areas: (1) Pucusana; (2) Paracas.Every one of them consisted in squares of 2 x 2 n.mi. surveyed 28times at 8 knots of speed. Labels such as ´C5´ indicates the place wherefifth fishing station (mid-water trawling) took place. There were executed21 fishing stations and and similar number of oceanographic casts (using CTD mainly)

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There were also used ´curtains´ or three-dimensional echograms built in Echoview to displaying under a clearer and enhanced perspective the time variation of the distribution of anchovy and munida. The purpose of it is in first place didactic in the sense that if makes easier the understanding of diel aggregation and vertical moves. Accordingly, the basic objective of this document is to at least describe one of the ways anchovy and munida interact in the ecosystem. Thus, data collected in Pucusana is presented as time series illustrating the variability of certain key-parameters regarding the diel cycle, the physical conditions of the zone and the availability of food (indexes of plankton abundance). In Paracas there were no significant presence of munida, what is a useful circumstance for comparative purposes to contribute to elucidate whether this crustacean inhibits or not de diel aggregation of anchovy. Time series were processed in worksheets. Statistical analysis was constrained to show the calculation of dispersion parameters (roughness, kurtosis, skewness etc) through SHAPES algorithm, without any further complex validations that certainly would require more extended time series. In our work we consider: the day is the period from 7 AM to 5 PM. The dusk is from 5 to 7 PM, the night is from 7 PM to 5 AM, and the dawn is from 5 AM to 7 AM. They are periods arbitrarily imposed according to moments when anchovy approximately appears to have defined forms in their schools.

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BFigure 3. Algorithm for identifying anchovy, munida and zooplankton (above). The panel below shows results of its application to produce typical echograms for day (A) and night (B). From left to right they appear ´W´, anchovy, munida and zooplakton echograms. Anchovy was detected by first filtering Sv values within a range from 4 to 25 dB to convolute the resulting matrix and detect the schools using SHAPES algorithm of Echoview to create data bases of morphometric parameters. After removing anchovy the detection of munida wasperformed. Zooplankton was detected filtering the ´W¨ echogram withim a threshold of –62 to –90 dB.

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Figure 4. 3D echograms as generated in Echoview. Every ´box´is a round to the studied zone in Pucusana. They are samples of the way anchovy form dense schools at day and disaggregated in microgroups at night. At the same time munida appears to just vertically disaggregate at night filling up the space. In: a) it is 8 AM, and anchovy schools appear well above munida´s long swarm layers; b) at 10 PM munida occupied vertically the space since it had already occupied it horizontally while anchovy disaggregated in near-surface microgroups; c) munida raised its lower limit of distribution while anchovy seems to show its denser microgroups less superficially.

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RESULTS 3D Structure Figure 4 shows three characteristic moments in the interrelation of anchovy and munida regarding their occupancy of space in the Pucusana zone: in a) during day anchovy schools are noticeable well above a deeper layer or swarm of munida though it exist a certain level of overlapping between them; in b) during first hours of night munida increases up toward surface its vertical distribution keeping its original deeper limit it had during the day while anchovy disaggregates in micro-groups near surface; in c) the vertical distribution of munida appears closer to surface during last part of the night while anchovy micro-groups appear a bit deeper. Patterns of diel distribution Most of the simultaneously measured parameters for anchovy and munida show a clear anti-symmetry in relation with the diel cycle. Figure 5 includes six parameters, four of which describe that distribution of the two species are placed in opposite phases: in a) the number of detected echo-traces during day is higher for munida than for anchovy, then the contrary occurs during the night; furthermore in b) acoustic density is higher for anchovy than for munida during the day though the reverse observation is made by night; in c) the mean high of echo-traces shows anti-symmetry too, when tall anchovy schools are observed during the day to drastically get reduced during the night while it occurs the opposite effect for munida; in d) the mean depth of anchovy

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Figure 5. Diel variation of some parameters related to schools and micro-groups of anchovy and swamrs of munida. According to what is shown in panels a to f it exist some kind of anti-symmetry between the way the two species are agreggated in the water column.

Figure 6. Vertical distribution of NASC (Nautical Area Scattering Coefficient, m2.mn-2) values by cells during a diel cycle for anchovy and munida in Pucusana. Top panel shows anchovy, middle panel shows munida, bottom panel is overlapping among the two species. Values over top axis en every panel are hours of the cycle while values below bottom axis are the ship´s log (n.mi.).

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Figure 6. Vertical distribution of NASC (Nautical Area Scattering Coefficient, m2.mn-2) values by cells during a diel cycle for anchovy and munida in Pucusana. Top panel shows anchovy, middle panel shows munida, bottom panel is overlapping among the two species. Values over top axis en every panel are hours of the cycle while values below bottom axis are the ship´s log (n.mi.).

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schools changes frequently though within a rather small range (from 10 to 15 m depth) while munida is distributed deeper during the day but superficially during the night; in e) there is a coincidence between length of echo-traces of anchovy and munida which are smaller during the day but longer during the night; finally in f) the horizontal roughness is minimum for munida during the day though higher during the night while anchovy got high roughness during day and night though with a curious reduction during dawn and dusk.. Overlapping Overlapping between anchovy and munida varies according with time, being higher during the night and little during the day. The diurnal overlapping is observed over the lower limit of the vertical distribution of anchovy and almost complete and closer to the surface during the night. Additionally the diurnal acoustic density of anchovy is bounded to the few dense big schools unlike the munida swarms whose acoustic density is smaller during the same time period though its distribution is far more uniform than anchovy. In night time the acoustic volume increases for munida swarms when them tend to get concentrated covering wider space close to the surface. See figure 6. The overlapping between anchovy and munida by cells shows a positive correlation, in which the higher the acoustic density is for one the denser will be for the other. It suggest that both species have the ability to co-occur as competitors in high proportions where it might exist bigger amounts of food (zooplankton). See figure 7a. The relationship between acoustic densities of anchovy and zooplankton looks lesser clear though they are not observed higher anchovy densities where low ones exist for zooplankton, what could suggest that anchovy is not interested in areas with no food (see figure 7b). Meanwhile munida seems to keep some kind of slight positive correlation with zooplankton, after all they both have wider vertical distributions than anchovy, then the probability of overlapping is higher. See figure 7c. The overlapping regarding depth is obviously bigger when the distribution of the species is shallower. It means what is commonly observed in marine ecosystems, that pelagic species converge near surface at night (Laevastu and Hayes, 1982). The percentage of vertical overlapping between anchovy and munida, and anchovy with zooplankton regarding depth is practically similar getting its higher values toward 15 m depth while the overlapping of munida and zooplankton is higher in general along the water column, getting its higher values between 20 to 25 m depth, what demonstrates their wider vertical distribution compared to that one of anchovy. See figure 7d.

Figure 7. Relationships between NASC scattering coefficients (m2.n.mi.-2) by cells (2 m hight x 0.25 n.mi. long) where anchovy, munida and zooplankton overlap: a) anchovy and munida; b) anchovy and zooplankton; c) munida and zooplankton. In d it is shown the porcentage of overlapped cells by depth. In e it is observed the porcentage of overlapped cells according to time cycle. In d and ethe overlapping of anchovy and munida appears in gross line, the overlapping of anchovy and zooplankton appear in thin line, andthe one for munida and zooplankton is shown in dotted line.

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Figure 7. Relationships between NASC scattering coefficients (m2.n.mi.-2) by cells (2 m hight x 0.25 n.mi. long) where anchovy, munida and zooplankton overlap: a) anchovy and munida; b) anchovy and zooplankton; c) munida and zooplankton. In d it is shown the porcentage of overlapped cells by depth. In e it is observed the porcentage of overlapped cells according to time cycle. In d and ethe overlapping of anchovy and munida appears in gross line, the overlapping of anchovy and zooplankton appear in thin line, andthe one for munida and zooplankton is shown in dotted line.

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Considering the diel cycle the overlapping has variations. In this case the tendency is again similar for anchovy with munida and zooplankton with higher values of concurrence during night time, what it matches with vertical migration. The case of munida regarding zooplankton is different because this two are partially overlapped most of time during the cycle though with higher indexes during the night. Nevertheless in this last case the overlapping after the dusk goes down abruptly, probably as an effect of what was noticed in the interpretation of figure 5c, that is that the lower limit of the vertical distribution of munida keeps its depth approximately until 20 PM when zooplankton has already moved to surface, then briefly though markedly reducing the overlapping. See figure 7e. Environmental differences between Pucusana and Paracas The acoustic surveys in Pucusana and Paracas were not interrupted to execute vertical oceanographic casts or fishing stations, these were performed after the two series were completed and lasted 24 hours. From the variables we used in this paper only surface temperature was recorded continuously during the 28+28 laps, then it is not possible to correlate the vertical distribution of species to the structure of the water column. Therefore new echograms were generated for the periods along which the casts and stations took place. In the figure 2 are noticed the locations of all the fishing stations, and figure 8 presents two echograms with superimposed key-oceanographic features: temperature (°C), salinity (ups), oxygen (ml.L-1) and chlorophyll (ug.L-1).

Ranges for temperature, salinity and oxygen in the water column have been very similar in Pucusana and Paracas, not chlorophyll, whose concentrations was very high in Paracas, what it is a clue of an intense

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a) Pucusana, temperature (°C)

b) Pucusana, salinity (ups)

c) Pucusana, oxygen (ml/L)

d) Pucusana, chlorophyll (ug/Lt)

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C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12C12 C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13C13 C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14C14 C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15C15 C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16C16 C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17C17 C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18C18 C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19C19 C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20C20 C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21C21

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e) Paracas, temperature (°C)

f) Paracas, salinity (ups)

g) Paracas, oxygen (ml/L)

h) Paracas, chlorophyll (ug/Lt)

Figure 8. Echograms obtained at 120 kHz showing superimposed oceanographic variables in the two studied zones during periods of around 24 hours. The four echograms of the column at left (a to d) correspond to the Pucusana zone during November 19-20, and those of the column at right are from Paracas (e to h) during November 22-23. In every echogram, left and right axis represents depth (in meters), the top axis is time of the day, and bottom axis shows labels for places when either oceanographic casts (indicated by entire value) or trawling (indicated by the prefix ´C´) took place. Every echogram shows a particular variable regarding the diel cycle distribution of anchovy and munida in Pucusana, and anchovy and mainly euphausiids in Paracas: in a and e it is shown the fluctuation of temperature (°C), in b and f it is visible the variation of salinity (ups), in c and g it is observed the oscillation of oxygen (mL.L-1), and, in d and h it is noted the variability of chlorophyll (ug.L-1).

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primary production. With the exception of the stable temperature in Pucusana in all the other cases it is displayed a noticeable vertical variability, what demonstrates de highly changing conditions of the coastal ecosystem. In both cases there were CCW the dominant water masses with a bit of influence of subtropical surface waters (SSW) in Pucusana, where the thermal, haline, oxygen and chlorophyll values till 50 m depth were within the usually observed range for anchovy and munida though the latter was practically absent of Paracas. The fishing stations and samplings with biological nets in Pucusana shown that the predominance in terms of abundance pointed out to anchovy followed up by munida (adult munida individuals can be considered part of micronekton, and younger stages –eggs, grubs and postgrubs- own to zooplankton community; R. Quesquén, pers. comm., 2005) and zooplankton (euphausiids, mainly). In Paracas the dominance was given up by anchovy, followed up by zooplankton (euphausiids, once again) and a very scarce presence of munida. The size histogram of anchovy was similar both in Pucusana and Paracas, with an unimodal structure of 15 cm of total length. In Pucusana anchovy was feeding on grubs and juveniles of munida and euphausiids as well, and mainly on euphausiids in Paracas (P. Espinoza, pers. comm., 2005). At a first glance during the survey munida was not considered as priority for the study, then lamentably it was not taken out detailed information on its size structure though it ranged between 20 to 25 mm of cephalotorax length. Nevertheless samples of individuals were collected for studies of trophic ecology. Differences in the anchovy patterns of aggregation With the exception of the high chlorophyll concentration in Paracas no noticeable differences exist in the environmental features of the two studied zones. Therefore one might expect the distribution, aggregation and diel migration of anchovy within the two areas to be quite similar, at least in general features. However the massive presence of munida in Pucusana might be a factor of inhibition in the aggregative diel dynamic of anchovy. It has been observed immediately after the dawn (4 AM) in Pucusana that some anchovy schools are well formed and aggregated in regions where the presence of munida is scarce or null. An example of it is shown in the figure 9.1 in whose upper-central part they appear well defined anchovy schools placed well above a layer or swarm of munida. At the same time in both sides of these schools still are observed scattered micro-groups of anchovy surrounded by munida. One hour later (figure 9.2) there are two well defined zones: at right there are well aggregated anchovy schools, and anchovy micro-groups still surrounded by munida at left. This might suggest that from 4:30 to 5:30 AM the process of aggregation take place for the two species, at least during spring. One more hour later (figure 9.3) all the region is crossed by a munida layer, and above it appear several anchovy schools (it is 6:30 AM by then). It is convenient to remember that during night time all anchovy micro-groups are wrapped up by the increased volume of that layer near surface, then in the extent where munida no longer saturates the space the aggregation of schools is facilitated. Depending on lunar phase this process might be accelerated by visual contact between individuals. If this inhibitor effect actually exist it is convenient to compare the aggregative patterns of anchovy in Pucusana and Paracas, zone practically ´free´ of munida. The same figure 9 shows eight comparative morphometric relationships that would demonstrate the conditioning effect of the presence of munida. All showed relationships (figures 9a to 9h) keep the same tendency in the two zones although there are subtle differences to validate the hypothesis of inhibition: in 9a the number of detected echotraces decays faster at dawn in Paracas so that the fragmentation in micro-groups there is slower at dusk; in 9b the perimeter of schools and micro-groups is uniform for the whole cycle in Paracas but in Pucusana it decays abruptly at dawn and increases quickly at dusk; as a verification the mean number of samples within schools and micro-groups (9c) and the mean length of these (9d) follow up very closely the same trend; in 9e and 9f they are shown the mean skewness and kurtosis, respectively, which describe a higher

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dispersion of values in Pucusana at dawn and dusk when compared to those ones in Paracas; in 9g the mean compactness grew up quicker at dawn in Paracas than in Pucusana though the trend is very similar in both cases; finally, in 9h the mean coefficient of variation of Sv samples reduces faster in Paracas at dawn, and follow up proximately the same trend at dusk.

DISCUSSION Our study supply two contributions regarding the way anchovy and munida interact in the ecosystem occupying the coastal space of NHCE. In first place we show the anti-symmetry in the diel cycles of aggregation-dispersion of both species. In second place it shows evidences of a inhibitor effect of munida on the aggregative dynamic of anchovy. Furthermore, ignoring biological aspects that lays in the field of trophic ecology we intended to rescue the concept of the role that munida might have in the NHCE. This means that munida could accomplish a more important function than it is usually assigned to it (Schweigger, 1964). The statement of Schweigger came up from his interpretation of fishery data but we think it could exist much more behind. In fact what we have studied so far is just a tiny part of a phenomenon we guess as complex as many other relationships that in fact exist in the NHCE. Of course we do not think in munidas eating anchovies but eggs of several species, then the least it can be said is that the function of munida is competence by interference than by predation, this is it, a contest for monopolization as suggested by Weir and Grant (2004). At the moment to pay renewed attention to munida it is convenient to take into account the collected information since munida ´reappeared´ in the NHCE, proximately in 1994, that suggest that its presence is linked to other processes that have happened more or less at the same time: the sustained influx of subantarctic waters into the coastal upwelling system, the cooling of the NHCE since 1998, the decreasing of coastal species, and the increase of their own population versus the amplification of the distributional areas of anchovy.

Figure 9. The possible effect of inhibition of the aggregation of anchovy in presence of munida in Pucusana as it is seem on 2D echograms. Echogram at left-top corner (1) was taken from 3:37 to 4:37 AM. Echogram at middle-left (2) was taken from 4:37 to 5:40 AM. Echogram at bottom-left corner (3) was taken from 5:40 to 6:42 AM. At right side they are placed eight key-relationships between the aggregative processes of anchovy in Pucusana and Paracas: from density and morphometric relationships and differences in the two zones it would be demonstrated that anchovy aggregates faster in zones with no presence of munida.

1, Lap 24

2, Lap 25

3, Lap 26

WELL FORMED ANCHOVY SCHOOLS,NO MUNIDA AROUND

ANCHOVY MICROGROUPS,MUNIDA SOURRONDING ALL OF THEM




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Figure 9. The possible effect of inhibition of the aggregation of anchovy in presence of munida in Pucusana as it is seem on 2D echograms. Echogram at left-top corner (1) was taken from 3:37 to 4:37 AM. Echogram at middle-left (2) was taken from 4:37 to 5:40 AM. Echogram at bottom-left corner (3) was taken from 5:40 to 6:42 AM. At right side they are placed eight key-relationships between the aggregative processes of anchovy in Pucusana and Paracas: from density and morphometric relationships and differences in the two zones it would be demonstrated that anchovy aggregates faster in zones with no presence of munida.

1, Lap 24

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3, Lap 26






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´Discovering´ munida Munida is not endemic to NHCE, in fact it was reported as exotic in the middle of the 1990 decade (Segura & Castillo, 1996). Since them its presence has been linked to subantarctic waters (SAW) influencing the NHCE. However Chirichigno (1970) and Haig (1955) generalize and reveal that munida or little red shrimp is distributed from 7°S in Peru till 42°S in Chile, always in upwelling areas of high primary and secondary production (Gallardo et al, 1980). Certainly munida has had an episodic presence in the south end of Peruvian coasts, then during those periods its was captured by catch in little amounts as accompanying fauna of established fisheries (Franco, 2003). However Schweigger (1964) and Del Solar (1942) describe high abundances during 1930 to 1950 decades, then the cycle is now repeated. Since 1998 its seasonal abundance (calculated through out acoustic methods) has been estimated over one million of tons, with a maximum of 3.4 millions during winter in 2000. The life history of munida describes in Chile a pelagic stage when grub, juvenil and young adult (Gallardo et al, 1980). In Peru munida has not been adequately studied, then we have been forced to look out for external references. Thus, the langostilla de California (Pleuroncodes planipes), specie very similar to munida, is basically a benthonic detritivorous during its adult life, while pelagic when younger whose diet is based on phyto and zooplankton, from diatoms to zoeas and eggs of crustaceans, euphausiids and copepods (Aurioles-Gamboa y Balart, 1995), therefore munida could also have those habits in the NHCE. Accordingly, when sharing space anchovy and munida would be competitors and together to practice a bottom-up control of their predators. Limitations One of the challenges of ecology is to explore and understand the phenomenon that regulate the distribution patterns of organisms across time and space (Greene & Wiebe, 1997) for which it exist a growing ability to acoustically study the biologic marine structures (Holliday, 2001). However, in our specific case it is good to keep in mind certain limitations. A big part of the obtained results are based upon the assumption that the used algorithm for identifying and discriminating between anchovy and munida, and for providing indexes of abundance of zooplankton, is efficient enough to support the performed analysis. The visual scrutiny of results of applying the algorithm has been satisfactory for daytime, and acceptable for the night time. However, the use of just two frequencies, and the important overlapping during the night introduces a bias of difficult mensuration. Besides, the hypothetical inhibition or difficulty of anchovy to aggregate in presence of munida is based upon morphometric measurements that are an interpretation of the acoustic information collected through the echosounder. The software for capturing and analyzing the 2D data has been designed keeping it in mind, though some papers such as those of Diner (1998) and ICES (2000) warn about the possible bias when reconstructing the geometrical shape of schools. The pulse rate of the echosounder and tilt angle of the fish when insonified constitute possible sources of bias as well (Holliday, 2001). The most important aspect to take into account before discussing results consist in the fact that schools, swarms and micro-groups are not static units, then very probably they have been moving in and out of our studied squares. From this point of view our results should be considered as synoptic, general features of the behaviour, of the dynamics of aggregation and of the interrelations of the studied species. These are the reasons why we have not applied rather complex statistical validations of the error or bias our results might contain. Its real mensuration would certainly need of more extensive time series. Strengths Our study is supported by a significant number of oceanographic casts and fishing stations which contributed to reduce the bias of the identification of targets though it already exist a certain level of experience regarding typical echotraces of anchovy and munida. We consider that the selection of the studied zones was right. In Pucusana the sea was absolutely calm what contributed to good acoustic

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measurements and without the disturbing effect of fishing ships that usually are encountered in the zone. In Paracas we had not that type of interference neither, with the advantage that no fish and little munida was detected but anchovy, which permits comparisons with Pucusana. The methodology of surveying continuously the same square is an efficient way to observe the diel aggregative-disperssive dynamics, facilitating the processing of data when having echograms of the same dimension for finding spatio-temporal variations. Also the use of 2D echograms extrapolated to a third dimension has probed to be valuable when finding patterns in the distribution of pelagic species (Greene & Wiebe, 1997). The avoidance of anchovy to the research vessel would not be important if we attend to results of the work done by Gerlotto et al (2004) in Chile on anchovy using a twin ship to RV Olaya. Besides preliminary results of this type of study at the moment underway in Peru coincide with the observation of little or null avoidance (F. Gerlotto, pers. comm., 2004). In the case of múnida its wider vertical distribution and its apparently limited swimming speed would make its avoidance negligible. The analysis ´by regions´ (fish schools, swarms or micro-groups) let us to directly compare the dimensions of aggregations and its variation with time and location in the water column. At the other hand the compartment of the space in ´cells´ of rather small dimension (0.25 n.mi. length, 2 m height) let us to compare the values of acoustic indexes and volumes in cells where the studied species co-occurring, which means that it is possible to study the progression of overlapping along the diel cycle. Differences in the diel dynamic of anchovy and munida From the simultaneously measured variables for anchovy and munida in Pucusana we choose six relationships that describe the mean variation of the diel aggregative dynamic of schools, swarms and micro-groups. From their interpretation we would say that there is a kind of anti-symmetry in four of them, coincidence in one (mean length) and completely different in the last one (mean depth). This means that it would exist evidence enough to say that the two species are placed in opposite phases regarding their aggregative dynamic. However that statement might not be categorical. The results of figure 5 contain one main debatable aspect: Looking at echograms collected during light time the swarms seems to have continuity (a long layer) in despite of apparent ´cuts´ along its structure, however the algorithm identify those cuts as separated swarms hence increasing the number of detected echotraces. It is possible that number of recordings (swarms) to be numerous though instead they might be vacuoles in the layer. At the other hand the number of swarms is small during night time but what it could be happening is that a huge munida swarms is formed at night, then it wrap up all schools and micro-groups in an apparently disorder way though occupying almost all available space. Figure 5 shows a positive correlation between length of schools and swarms for the whole cycle though, in this case for the reasons before explained, the length of diurnal swarms might be longer, then this apparent correlation could be espureous. Dynamic of diel overlapping The overlapping of anchovy and munida is reduced during the day (less than 10% of the vertical space till 50 m depth) tough high during night time. The diurnal overlapping would occur by chance, as the product of the sinuosity of swarms-layers of munida which eventually goes up temporarily following up the oxycline than by real concurrency of the two species toward a particular attracting zone. In the same sense the overlapping at dawn and dusk would be the unavoidable product of the vertical migration of munida up to the surface. Then the true overlapping is given near surface during the night, where more than 40% (around 2 AM) of the space till 50 m depth, and 35% considering the whole cycle is space devoted to overlapping (see figures 7d and 7e). From 8 PM to 5 AM practically all anchovies are wrapped up by big “inflated” munida swarms. A very similar process is observed for anchovy regarding zooplankton either in relation with depth and diel cycle, which means that vertical migration patterns of munida and zooplankton appear proximately

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the same. Within the scope of this work we do include young and grub estages of munida as a component of zooplankton, which were found in the stomachs of anchovies sampled after fishing stations in Pucusana. There, the diet of anchovy was also composed by euphausiids while munida must have been feeding on phytoplankton, eggs of fish and euphausiids depending on its biologic stage (P. Espinoza, pers. comm., 2005). The overlapping among munida and zooplankton is placed around 20% of vertical space till 50 m during the complete cycle with the exception of the period between 5 to 8 PM, when the overlapping fall down to later increase till reach its maximun values (35%). This would happen because munida increases its vertical distribution through keeping its lower deep border -and even keep it until 7 PM- that it is a time when zooplancton already moved to surface. Of course, as it was mentioned before, we consider younger stages of munida as component of zooplankton, then, in preys for others. NASC values within cells where it took place the overlapping between anchovy and munida had a positive correlation which would denote the ability of the two species to finding the more dense places with food. At the same time the two species have positive correlations with zooplankton. This of course is not strange as noted by Pitcher (1986) regarding his explanation of ideal free distribution, which predicts that foraging populations distribute themselves among available food. Certainly the way we calculated our indexes of abundance for zooplankton –generally distributed over 30 m- is not the best (it just was set a threshold from –65 to –90 dB to exclude of the echogram the recordings due to fish and micronekton), tough Bertrand et al (2005) have found a suitable correlation between our indexes and those found through the use of multinet sampler system and traditional counting in laboratory. Environmental aspects The environmental variables were measured after the experiments (the 28+28 laps in Pucusana and Paracas) during a complete diel cycle. Thus the oceanographic features of the water column shown that they have not existed extreme situations in which anchovy and/or munida have been forced out to drastic changes on their behaviour in despite of the noticeable variability of parameters such as oxygen and chlorophyll, this is, all values have been measured within the known limits of tolerance for the two species. However the collected echograms simultaneously to CTDO casts correspond to erratic no regular paths, then it is difficult to extract comparable information from them. Instead it is possible to observe (figure 8) that patterns of vertical distribution are the same than those observed during the laps. The only noticeable difference would be the apparent increase of zooplankton in Paracas, probably due to the high concentration of chlorophyll and primary production. According to salinity values the water masses in the two zones are CCW though haline concentration was a bit higher in Pucusana (35.05 ups) due to the nearly influence of SSW. It has come to be common that munida is found in mixed waters (CCW-SSW), but a few years ago we did not observe it in these water types. What seems to be obvious, though still not demonstrated, is that munida would be developing capacities of adaptation in front of situations theoretically adverse. Munida, by catch, inhibition The experiments in Pucusana and Paracas have been executed during a season (austral spring) when normally the influx of SSW started to being notorious in the ecosystem (higher temperatures and salinities than during winter). Wide zones covered up by CCW goes back on the coast generating a front where they are congregated the denser clusters of anchovy and, of course, munida. It is in this period of the year when the higher catches of anchovy are reached up. Peruvian fishermen are already accustomed to by catches of munida when fishing on anchovy, and even the catches composition have many times had higher contribution of munida.

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Munida has not an industrial revenue in Peru, and machinery for transforming the fish into fish meal suffer malfunctioning when they are supplied with massive amounts of the crustacean. The fishermen also do consider as a ´punishment´ the catch of munida not only because its low or null economic value but for the extended journeys to sea due to the necessary cleaning of the nets (munida greatly get trapped in the meshes of the purse seine nets). No official statistics exist regarding the amount of munida that is extracted by catch, so it is not a specie under governmental fishery management. The efficient fishermen –skkipers- have learned to discriminate between the recordings of anchovy and munida, so they are in better position for avoiding the by catch. They also know that munida does not distribute in the coast if the depth out there is shallower than it need for its daily migration. They know that not always anchovy and munida congregate together near surface at night though always it exist a clear vertical stratification during the day. Then, the study of the effect of the presence of munida in the aggregation of anchovy might conduce to reduce the by catch (e.g. forbidding the catches in coastal areas during the dusk, night and dawn). Our results would demonstrate in general features that the presence of munida inhibits the aggregative pattern of anchovy either by physical or visual interference at dawn and dusk. Several morphometric relationships shows that anchovy aggregates faster and disaggregate slower when munida is absent. Schemes of occupancy of the space To synthesize the spatio-temporal dynamic and interactions of diel cycles of aggregation we produced the figure 10 to schematically reproduce the way in which anchovy and munida were distributed in Pucusana. The main difference is the plain or vertically static vertical distribution of anchovy in contrast with the sinuous aggregation of munida. The projections of figure 10 are lines of tendency regarding the location of upper and lower limits of distribution, as well as the tendencies for maximal and minimal Sv values along the diel cycle in the water column. In both cases it is relevant the parallelism that it exist between the upper limits and the limits of maximal acoustic density (and even the lower limit in the case of munida). It is also relevant that the lower limits of distribution do not match with the line of minimal acoustic densities. As a difference the line of lower Sv value seems to respond to a estochastic nature. These synoptic features would demonstrate that for both species exist a vertical structured distribution, deterministic, non aleatory, with defined diel patterns and synchronized aggregative processes. It is now required a wider scale study though very specially to analyze the functional relationships between the two species in order to know by instance at what extent munida would predate on fish eggs, and what is the predation of anchovy on munida juveniles and grubs.

Figure 10. Schematic presentation of the way anchovy and munida aggregated in Pucusana according to strength of backscattered volume (Sv, dB.m-1). In a anchovy shows its ´plane´ pattern. In b munida vertical diel migration is clearly seem. All lines are trends calculated through out polinomic regressions.

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Figure 10. Schematic presentation of the way anchovy and munida aggregated in Pucusana according to strength of backscattered volume (Sv, dB.m-1). In a anchovy shows its ´plane´ pattern. In b munida vertical diel migration is clearly seem. All lines are trends calculated through out polinomic regressions.

a) Anchovy Sv vertical distribution

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b) Munida Sv distribution

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CONCLUSIONS Anchovy and munida shown some opposed phases, anti-symmetrical, in their strategy of occupancy of the space though coincidences too regarding their diel cycle of aggregation during an experiment carried out in a small zone near to Pucusana, Peru. It means that anchovy congregated in dense tall schools during the day to get dispersed in micro-groups during the night, while munida did in long acoustically weaker thin swarms (´layers´), to get closer to surface as well as anchovy does from dusk to dawn increasing vertically its volume that wraps up anchovies. Overlapping of anchovy and munida is poor during the day and wide during the night. Vertically the overlapping is important near surface. The same pattern has been observed for anchovy regarding zooplankton, though munida and zooplankton kept vertically a much higher overlap between them along the whole diel cycle. In all cases there were positive correlations of acoustic density where anchovy, munida and zooplankton overlapped. According to a visual scrutiny and a comparative approach between vertical distributions of anchovy in Pucusana and in a second experimental zone (Paracas), the massive presence of munida in the first location inhibited the formation of anchovy schools at dawn either by physical or visual interference. The environmental conditions in Pucusana and Paracas were closely similar, and oceanographic features were within usually observed ranges for these species, then results of the experiments would not be influenced by sudden changes in normal behavior. Using the gathered information and analysis it has been schematized the vertical structure of aggregation for anchovy and munida in Pucusana. It shows in both cases that it would exist some kind of parallelism between the depth of upper and lower limits of vertical distribution with that of the maximal acoustic density, while it appeared erratic the depth of lower limit of acoustic density. This knowledge of the way anchovy and munida aggregate and interact can conduce to reduce the uncertain amount of by catch of munida in the Peruvian fisheries. Acknowledgements The authors sincerely thank the Peruvian Marine Research Institute (IMARPE) for having facilitated the use of the data for this work as well as to Captain Erik Salazar and crew of RV Olaya for their patience and support. We also sincerely thank to Jesus Ledesma, Roberto Quesquen and Pepe Espinoza from IMARPE for providing data and valuable comments, and Arnaud Bertrand from IRD, for their useful suggestions. This work is a contribution of the Study Group CARDUMEN from IMARPE, of the Research Unit 'Eco Up' UR097, and of the Interdepartmental Thematic Action "Humboldt Current System’’ from IRD. Referencias Alheit J. & M. Ñiquen. 2004. Regime shifts in the Humboldt Current ecosystem. Progress in Oceanography xxx (2004) xxx–xxx. (in edition). Arias-Schereiber M. 1996. Informe sobre el estado de conocimientos y conservación de los mamíferos marinos en el Perú. Inf. Prog. Inst. Mar Perú N°38. 30 pp. Arntz W., & E. Fahrbach. 1996. El Niño: experimento climático de la naturaleza. Fondo de Cultura Económica, primera edición. 312 pp. Aurioles-Gamboa D. 1991. Ciclo migratorio de la langostilla Pleuroncodes planipes: Importancia para su explotación pesquera en México. Programa y Resúmenes del IV COLACMAR, Chile. 112 pp.

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Bahamonde R., G. Henriquez, P. Pavez, B. Ramírez y N. Silva. 1979. Evaluación de los recursos de camarón y langostino entre Coquimbo e Isla Mocha. Inf. Presentado a la Corporación de Fomento de la producción. AP 79-46: 194 pp. Bertrand A., M. Segura, M. Gutierrez & L. Vasquez. 2004. From small-scale habitat loopholes to decadal cycles: a habitat-based hypothesis explaining fluctuation in pelagic fish populations off Peru. Fish and Fisheries (5) 296–316. Bertrand A., M. Gutiérrez, S. Bertrand, P. Espinoza, F. Gerlotto, J. Ledesma, R. Quesquén, L. Alza, S. Peraltilla & F. Chavez. 2005. How fish habitat suitability does shape the 3D spatial organisation of anchovy across scales ?. In edition. Boerema L.K., G. Saetersdal, I. Tsukayama, J. Valdivia & B. Alegre. 1965. Report on the effects of fishing on the peruvian stock of anchovy. FAO Fish. Tech. Pap. 55, Rome, 44 pp. Chavez, F.P., Ryan, J., Lluch-Cota, S.E. and Niquen, M. 2003. From anchovies to sardines and back: multidecadal change in the Pacific Ocean. Science 299, 217–221. Chirichigno, N. 1970. Lista de crustáceos del Perú (Decápodos y Stomatopodos) con datos de su distribución geográfica. Inf. Inst. Mar Perú N° 35: 1-95. Clarke F.N. 1954. Biología de la anchoveta. Bol. Cient. Admin. Guano 1(1):98-132. Csirke J. 1980. Recruitment in the Peruvian anchovy and its dependence on the adult population, pp 307-313. In A. Saville (ed.) The assessment and management of pelagic fish stocks. Rapp. P.-V. Réun. Cons. Int. Explor. Mer 177. Dawkins R. 1989. The selfish gene. Oxford University Press. 352 pp. Del Solar E. 1942. Ensayo sobre la ecología de la anchoveta. Bol. Comp. Admin. Guano. Vol. XVIII, Lima. Diner, N. 1998. Correction on school geometry and density. In ICES C.M. 1998/B:1 Doe, L.A.E. 1978. Project ICANE: a progress and data report on a Canada-Peru study of the Peruvian anchovy and its ecosystem. Bedford Institute of Oceanography, Rep. Ser. #BI-78-6. 211p. Elliott W & F. Paredes. 1996. Estructura especiológica del subsistema costero. Prospección 9512-9601. En: Prospección de los Recursos Costeros que sustentan la Pesquería Artesanal. L/P San Jacinto, de Puerto Pizarro a Ilo. Inf. Inst. Mar Perú NC 121: 14-26. Espino M. 2003. Estrategia de gestión ambiental para el Pacífico Oriental con especial mención a la pesquería peruana. Tesis. Universidad Nacional Mayor de San Marcos. 102 pp. Franco M. 2003. Aspectos biológico-pesqueros del camarocito rojo Pleuroncodes monodon (M. Edwards, 1837) en el litoral peruano. Tesis. Universidad Nacional del Callao. 62 pp. Fréon P. & O. Misund. 1999. Dynamics of pelagic fish distribution and behaviour: effects on fisheries and stock assessment. Fishing News Books. 348 pp. Greene C., & P. Wiebe. 1997. Acoustic visualization of three-dimensional animal aggregations in the ocean. In: Animal Groups in Three Dimensions. Press Sindicate of The University of Cambridge. 61-67. Greenlaw C. F. 1983. Multiple frequency acoustical estimation. Biological Oceanography, Vol. 2, Number 2-3-4.

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Gulland J. 1968. Report on the population dynamics of peruvian anchovy. FAO Fish. Tech. Pap. 72. Rome, 29 pp. Gallardo V., E. Bustos, A. Acuña, L. Diaz, V. Erbs, R. Meléndez & L. Oviedo. 1980. Relaciones ecológicas de las comunidades bentónicas y bentodemersales de la plataforma continental de Chile Central. Informe División de asistencia Técnica, Dirección de Investigación, Universidad de Concepción, a Subsecretaría de Pesca (mimeo): 325 págs. Gerlotto F., J. Castillo, A. Saavedra, M. A. Barbieri, M. Espejo & P. Cotel. 2004. Three dimensional structure and avoidance behaviour of anchovy and common sardine schools in central southern Chile. ICES Journal of Marine Science, 61: 1120-1126. Gutiérrez M., G. Swartzman, A. Bertrand, S. Bertrand. 2005. Anchovy and sardine spatial dynamics and regime shifts: new insights from acoustic data in the Humboldt Current System, Peru, from 1983-2003. Fish and Fisheries (in edition). Gutiérrez M., R. Castillo, F. Ganoza, N. Herrera, y S. Peraltilla.2001. Análisis de la distribución y abundancia de algunos recursos pelágicos peruanos acústicamente evaluados en la primavera. Inf. Inst. Mar Perú Vol. 32(2): 167-180. Gutiérrez M., S. Peraltilla. 2005. Evaluación acústica de la distribución y abundancia de especies pelágicas y mesopelágicas durante el invierno de 2004. Inf. Inst. Mar Perú (in edition). Haig J. 1955. The crustacea anomura of Chile. Reports of the Lund University. Chile Expedition 1948-49. 68 pp. Higgimbottom I.R., Pauly, T.J. & Heatley D.C. 2000. Virtual echograms for visualization and post-processing of multiple-frequency echosounder data. Proceedings of the Fifth European Conference on Underwater Acoustics, ECUA 2000 (Ed. M.E. Zakharia), 1497-1502. ICES. 2000. Report on Echotrace Classification. ICES Cooperative Research Report N° 238. 115 pp. Jahncke J., A. García-Godos & E. Goya. 1997. Dieta del guanay Leucocarbo boougainvilii, del piquero peruano Sula variegata y otras aves de la costa peruana en abril y mayo de 1997. Inf. Inst. Mar Perú N°126: 75-88. Jordan R. 1971. Distribution of anchoveta (Engraulis ringens J.) in relation to the environment. Inv. Pesq. 35(1): 113-126. Laevastu T. & M. Hayes. 1982. Fisheries oceanography and ecology. Fishing News Books. MacLennan D.N. & J. Simmonds. 1992. Fisheries Acoustics. Chapman and Hall, London. Mayr E. 1963. Populations, Species and Evolution. The Belknap of Harvard University Press. 453 pp. Palma, S. 1994. Distribución y abundancia de larvas de langostino colorado Pleuroncodes monodon frente a la costa de Concepción, Chile. Invest. Mar Valparaíso, 22: 13-29 Parrish J., W. Hamner & C. Prewitt. 1997. From individuals to aggregations: unifying properties, global framework and the holy grails of congregation. Animal Groups in Three Dimensions. Press Sindicate of The University of Cambridge. 376 pp. Pauly D., I. Tsukayama & H. Tovar. 1986. Some preliminary results from an international multidisciplinary project aimed at reconstructing monthly time series on the Peruvian ecosystem for the years 1953-1982. Paper presented at the Chapman Conference on El Niño: an International Symposium, Guayaquil, Ecuador, 27-31 October 1986 (pp. 25-26 in Vol. Of Abstracts).

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Pitcher T. 1986. Behaviour of Teleost Fishes. Chapman and Hall, London. Schweigger E. 1964. El litoral peruano. Editorial de la Universidad Nacional Federico Villarreal. 2da. Ed. 440 pp. Segura M. y R. Castillo. 1996. Distribución y concentración de la múnida (Pleuroncodes monodom) en el verano 1996. Inf. Inst. Mar Perú (122): 79-85. Holliday D. V. 2001. Acoustical sensing of biology in the sea. Acoustical Oceanography. Proc. Institute of Acoustics Vol. 23 Part 2. Weir L. & J. Grant. 2004. The causes of resource monopolization: interaction between resource dispersion and mode of competition. Ethology 110: 63-74.

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