Assessing the sensitivity and specificity of fish community indicators to management action

2012 ◽  
Vol 69 (6) ◽  
pp. 1065-1079 ◽  
Author(s):  
Jennifer E. Houle ◽  
Keith D. Farnsworth ◽  
Axel G. Rossberg ◽  
David G. Reid
Keyword(s):  
Sensitivity And Specificity ◽  
Fish Community ◽  
Ecosystem Approach ◽  
Large Species ◽  
Fishing Pressure ◽  
Fishing Mortality ◽  
Size Selection ◽  
Community Model ◽  
Community Monitoring ◽  
Specific Biomass

We assessed ten trophodynamic indicators of ecosystem status for their sensitivity and specificity to fishing management using a size-resolved multispecies fish community model. The responses of indicators to fishing depended on effort and the size selectivity (sigmoid or Gaussian) of fishing mortality. The highest specificity against sigmoid (trawl-like) size selection was seen from inverse fishing pressure and the large fish indicator, but for Gaussian size selection, the large species indicator was most specific. Biomass, mean trophic level of the community and of the catch, and fishing in balance had the lowest specificity against both size selectivities. Length-based indicators weighted by biomass, rather than abundance, were more sensitive and specific to fishing pressure. Most indicators showed a greater response to sigmoid than Gaussian size selection. Indicators were generally more sensitive at low levels of effort because of nonlinear sensitivity in trophic cascades to fishing mortality. No single indicator emerged as superior in all respects, so given available data, multiple complementary indicators are recommended for community monitoring in the ecosystem approach to fisheries management.

scholarly journals Tracking the changes of a fish community following a megascale reclamation and ensuing mitigation measures

2013 ◽  
Vol 70 (6) ◽  
pp. 1206-1219 ◽  
Author(s):  
Yin-Ki Tam ◽  
I-Hsun Ni ◽  
Cynthia Yau ◽  
Man-Yee Yan ◽  
Wai-Shan Chan ◽  
...  
Keyword(s):  
Community Structure ◽  
Community Health ◽  
Fish Community ◽  
Time Lag ◽  
Mitigation Measures ◽  
Fish Density ◽  
Dynamic Factor ◽  
Large Species ◽  
Fishing Pressure ◽  
Fast Growing

Abstract Tam, Y-K., Ni, I-H., Yau, C., Yan, M-Y., Chan, W-S., Chan, S-M., Lu, H-J. 2013. Tracking the changes of a fish community following a megascale reclamation and ensuing mitigation measures. – ICES Journal of Marine Science, 70: 1206–1219. A fish community in Hong Kong that had experienced megascale reclamation in Chek Lap Kok International Airport, and the ensuing marine protected areas (MPAs) establishment was tracked for 12 years. Significant shifts in community structure, typified by 17 species, were revealed by multivariate analyses and community metrics. Dynamic factor analysis disclosed two underlying common trends among them and their significant correlations with changes in water quality, area of seabed disturbance, and area of MPAs. A time-lag for detectable community changes was also revealed. During reclamation, the fish density was low and community health was poor. Large species disappeared leaving a community dominated by small, fast-growing and young-to-mature species. After completion of reclamation, some large and medium species returned, but soon after the establishment of MPAs, medium-sized, fast-growing and young-to-mature species thrived on reduction of fishing pressure, and filled the guilds rapidly. Therefore, even though fish density and community health were improved, the original community structure was not restored. This study provides a good reference for impacts of reclamation at the community level and the possible outcomes of reducing fishing pressure in a depleted fish community.

scholarly journals INTER-SPECIFIC COMPETITION AND FISHING EFFECT TO POPULATION DYNAMIC OF BALI SARDINE (SARDINELLA LEMURU)

2017 ◽  
Vol 22 (2) ◽  
pp. 85
Author(s):  
Andhika Prima Prasetyo ◽  
Rudy Masuswo Purwoko
Keyword(s):  
Mortality Rate ◽  
Population Dynamic ◽  
Positive Response ◽  
Fishing Pressure ◽  
Fishing Mortality ◽  
Precautionary Approach ◽  
Dramatic Decline ◽  
Stock Recruitment ◽  
Juvenile Population ◽  
Relationship Of

Stock-recruitment relationship of Bali sardine was investigated based on Beverton-Holt model by assuming inter-specific competition. Model is modified to incorporate the effect of fishing pressure that is density-independent to population dynamic by developing scenario fishing on adult and/or juvenile population. The results show that harvested adult the dramatic decline of recruitment supply. However, harvested juvenile is led to the positive response to population size, as an increase in fishing mortality rate will reduce competition mortality rate. Precautionary approach required by considering bipartite life cycle. 

scholarly journals Overlooked biological and economic implications of within-season fishery dynamics

2014 ◽  
Vol 71 (2) ◽  
pp. 181-188 ◽  
Author(s):  
Xiaozi Liu ◽  
Mikko Heino
Keyword(s):  
Concentration Profile ◽  
Fishing Effort ◽  
Economic Consequences ◽  
Fish Abundance ◽  
Fishing Pressure ◽  
Fishing Mortality ◽  
Economic Implications ◽  
Special Cases ◽  
Total Stock ◽  
Stock Abundance

Catch equations relate fisheries catch to initial fish abundance and the applied fishing pressure. The Baranov catch equation, often simply referred to as the catch equation, is the commonest one. However, there are exactly three ways of describing seasonal progression of fishing parsimoniously with a single parameter: assume catch rate, fishing effort, or fishing mortality is constant, the last being the assumption underlying the Baranov catch equation. These assumptions imply different dynamics, and only in special cases two of these assumptions can hold true simultaneously. Whether this happens is dictated by the concentration profile (i.e., the dependence of mean fish density where fishing takes place on total stock abundance). We show that the assumed seasonal progression of fishing and the type of the concentration profile have major implications for fishery dynamics as well as biological and economic consequences of fishing, calling for increased awareness of these overlooked assumptions of fishery dynamics. However, in many cases the Baranov catch equation serves as a good approximation, even when its assumption of constant fishing mortality is violated.

scholarly journals 2005 Annual Synthesis Report, Pallid Sturgeon Population Assessment Program and Associated Fish Community Monitoring for the Missouri River

2008 ◽  
Author(s):  
Eric W. Oldenburg ◽  
Timothy P. Hanrahan ◽  
Ryan A. Harnish ◽  
Brian J. Bellgraph ◽  
Joanne P. Duncan ◽  
...  
Keyword(s):  
Fish Community ◽  
Missouri River ◽  
Population Assessment ◽  
Assessment Program ◽  
Pallid Sturgeon ◽  
Community Monitoring ◽  
Synthesis Report

Accounting for variation in species detection in fish community monitoring

2013 ◽  
Vol 21 (2) ◽  
pp. 96-112 ◽  
Author(s):  
R. A. McManamay ◽  
D. J. Orth ◽  
H. I. Jager
Keyword(s):  
Fish Community ◽  
Species Detection ◽  
Community Monitoring

Externally driven changes in the abundance of summer and winter flounder

2014 ◽  
Vol 71 (9) ◽  
pp. 2416-2428 ◽  
Author(s):  
Richard J. Bell ◽  
Jonathan A. Hare ◽  
John P. Manderson ◽  
David E. Richardson
Keyword(s):  
Climate Variability ◽  
Water Temperature ◽  
Large Scale ◽  
Local Level ◽  
The United States ◽  
Winter Flounder ◽  
Fishing Pressure ◽  
Fishing Mortality ◽  
Summer Flounder ◽  
Decadal Scale

Abstract Marine organisms that utilize nearshore environments for major components of their life histories are subject to both local-scale forcing such as water quality and estuarine degradation as well as large-scale forcing such as fishing and decadal-scale climate variability. Large-scale forcing has the potential to synchronize the dynamics of subpopulations, while local-level forcing can produce asynchronous subpopulation trends. Summer flounder (Paralichthys dentatus) and winter flounder (Pseudopleuronectes americanus) are important commercial and recreational flatfish along the east coast of North America which spend their first year of life in coastal habitats. We found that the two exhibited significant within-species coherence in commercial landings and fisheries-independent surveys across the northeast shelf of the United States, suggesting large-scale external drivers. In laboratory studies, temperature has been found to be an important factor regulating survival during the egg, larva and settlement phases of both species. We reconstructed a 40-year time-series of coastal water temperature for the major spawning and nursery areas to examine changes in the thermally available habitat. Estimates of winter flounder abundance were negatively correlated with the winter water temperature, but not with fishing mortality. Summer flounder abundance, by contrast, was negatively correlated with fishing mortality, but exhibited no link with temperature. In addition, time-varying stock–recruitment relationships indicated that stock productivity declined for winter flounder over time, while summer flounder productivity has varied without a trend. While both species declined in the 1980s and early 1990s due to heavy fishing pressure, the reduction in fishing over the last two decades has led to rebuilding of the summer flounder stock and an expansion of its age structure. Declining productivity due to warming estuarine conditions has kept the winter flounder stock at low levels despite low fishing pressure. The two stocks illustrate the importance of controlling fishing mortality in the management of natural marine resources while also accounting for changes in productivity due to climate variability and change.

scholarly journals Modelling the direct impact of bottom trawling on the North Sea fish community to derive estimates of fishing mortality for non-target fish species

2009 ◽  
Vol 66 (9) ◽  
pp. 1985-1998 ◽  
Author(s):  
G. J. Piet ◽  
R. van Hal ◽  
S. P. R. Greenstreet
Keyword(s):  
North Sea ◽  
Fish Species ◽  
Fish Community ◽  
Direct Impact ◽  
Fishing Mortality ◽  
Bottom Trawling ◽  
The North ◽  
Target Fish ◽  
The North Sea ◽  
Sea Fish

Abstract Piet, G. J., van Hal, R., and Greenstreet, S. P. R. 2009. Modelling the direct impact of bottom trawling on the North Sea fish community to derive estimates of fishing mortality for non-target fish species. – ICES Journal of Marine Science, 66: 1985–1998. This study introduces a spatially explicit model that combines abundance data for all the main fish species in the demersal North Sea fish community with international effort data and estimates of gear-, species-, and size-dependent catch efficiency to determine the mortality of non-target fish species caused by bottom trawl fisheries and its spatial variation. Where necessary information was lacking, assumptions were made, and a sensitivity analysis performed to examine the impact of these issues on model results. Model outcomes were validated using international landings and discard data for five target species: cod, haddock, whiting, sole, and plaice. This showed that depending on its configuration, the model could reproduce recorded landings and discards of these species reasonably well. This suggests that the model could be used to simulate rates of fishing mortality for non-target fish species, for which few data are currently available. Sensitivity analyses revealed that model outcomes were most strongly influenced by the estimates of gear catch efficiency and the extent to which the distributions of fishing effort and each species overlapped. Better data for these processes would enhance the contribution that this type of model could make in supporting an ecosystem approach to fisheries management.

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