fishing the marine food web along the indian coast
DESCRIPTION
Fishing the marine food web along the Indian coast. 印度沿岸水域因 漁業捕撈影響食物網變動情形. Fisheries Research 74 (2005) 223–231. E. Vivekanandan*, M. Srinath, Somy Kuriakose. 報告者 : 何珈欣. Outline. Introduction Objectives Material & Method Result Discussion and conclusions. Introduction. NW COAST. - PowerPoint PPT PresentationTRANSCRIPT
Fishing the marine food web along the Indian coast
E. Vivekanandan*, M. Srinath, Somy Kuriakose
Fisheries Research 74 (2005) 223–231
印度沿岸水域因漁業捕撈影響食物網變動情形
報告者 :何珈欣
Outline
Introduction
Objectives
Material & Method
Result
Discussion and conclusions
Introduction
INDIA NE COAST
SE COASTSW COAST
NW COAST
BAY OF BENGAL
ARABIAN SEA
Indian
Objectives
Pauly et al. (1998) called “fishing down marine food webs”.
Along the Indian coast, there has been an unprecedented expansion of fishing fleets in the last half century in the present paper, the trend in fishing the marine food web along the Indian coast during 1950–2002 has been analysed.
Material & Method
Mean trophic level(MTL)
Fishing-in-balance index(FIB)
Trophic category
Statistics of Indian coast catch
MTL :The mean trophic level of landing in year j
Yij :The landing of species i in year j
TLi :the trophic level of species i
Mean trophic level(MTL)
ij
ijij
Y
YTLMTL
Material & Method-1
4
3
2
Top predator
Herbivores Omnivores
Mid-level carnivores
Material & Method-1
Trophic levels
Yi :Landing at year i
TE:trophic efficiency (here set at0.10)
Y0 and TL0 are the landing and mean TL of the first year of the series
Fishing-in-balance index(FIB)
TLoTLi
TE
1O
TE
1i Ylog-YlogFIB
Material & Method-2
Material & Method-2
110
100
1000-0. 3-0. 2-0. 1
00. 10. 20. 30. 40. 50. 6
1950 1957 1964 1971 1978 1985 1992 1999Year
FIB
inde
x
FI B i ndex
FiB=0
Trophic levels
FiB=(+)
110
100
1000
Material & Method-2
Trophic levels
110
1001000
FiB=(-)Material & Method-2
Trophic levels
Trophic category
Trophic category 1 (TrC1) herbivores, detritivores and omnivores (TL:2.00–3.00)
Trophic category 2 (TrC2) mid-level carnivores (TL: 3.01–3.50)
Trophic category 3 (TrC3) high-level carnivores and top predators (TL: >3.51)
Material & Method-3
Trophic category 1 (TrC1) Material & Method-3
Vivekanandan et al., in press
Trophic category 2 (TrC2)
Mid-level carnivores (TL: 3.01–3.50)
Material & Method-3
Mid-level carnivores (TL: 3.01–3.50)
Material & Method-3Trophic category 3 (TrC3)
Result
NW
SW
SE
NE
Result
Period NW SW NE SE TrL FiB TrC TrL FiB TrC TrL FiB TrC TrL FiB TrC
1953-1962 3.27 0.48 TrC3 3.12 -0.22 TrC2 3.32 -0.18 TrC2 3.52 0.03 TrC21963-1972 3.33 0.49 TrC3 2.94 -0.16 TrC1 3.28 0.13 TrC2 3.51 0.19 TrC21973-1982 3.34 0.76 TrC3 3.09 0.06 TrC2 3.27 0.52 TrC2 3.48 0.36 TrC21983-1992 3.38 0.96 TrC3 3.21 0.33 TrC2 3.33 0.87 TrC2 3.43 0.41 TrC21993-2002 3.38 1.13 TrC3 3.28 0.46 TrC2 3.22 0.99 TRC2 3.32 0.45 TRC2
Mean 3.32 0.72 3.14 0.09 3.29 0.43 3.45 0.27CV 2.8 43.1 5.4 312.7 2.6 113.4 2.3 66
Table 1Decadal changes in mean TrL and FIB and TrC values
TrC2 TrC2
Result Southwest coast (SW)
Trends in parameters related to fishing the food web along the southwest coast
Trends in parameters related to fishing the food web along the southeast coast
Southeast coast (SE)
Result
1980
Indian coast
Trends in parameters related to fishing the food web along the Indian coast
Discussion
1.The Environment condition
2.Advancement of fishing technologies
Table2.Corrleation analysis of TrL and FIB with total catch and catch of each TrC
Corrleation analysis of TrL and FIB with total catch and catch of each TrC
Discussion-1
The Environment condition
The surface chlorophyll and the biomass of benthic organisms in the Arabian Sea is very high compared to the Bay of Bengal in the east coast .
Whereas upwelling enhances the productivity and abundance of planktivores along the SW and abundance of demersals along the NW coast. Along the SW the fishery is driven by upwelling and other environmental variabilities, and rarely shows stability.
Table1.Fisheries profile of four coastal zones in the Indian mainland
Advancement of fishing technologiesDiscussion-
2
Discussion-2
Advancement of fishing technologies
Fishing the food web could be influenced by the impacts of advancement of fishing technologies.
The trawlers progresses continuously during the 1960~2000.
Thank You