Spatial patterns of fishing effort off San Diego: implications for zonal management and ecosystem function

2010 ◽  
Vol 20 (8) ◽  
pp. 2203-2222 ◽  
Author(s):  
P. Ed Parnell ◽  
Paul K. Dayton ◽  
Rachelle A. Fisher ◽  
Cina C. Loarie ◽  
Ryan D. Darrow
Author(s):  
James P. Barry ◽  
Stephen Widdicombe

The biodiversity of the oceans, including the striking variation in life forms from microbes to whales and ranging from surface waters to hadal trenches, forms a dynamic biological framework enabling the flow of energy that shapes and sustains marine ecosystems. Society relies upon the biodiversity and function of marine systems for a wide range of services as basic as producing the seafood we consume or as essential as generating much of the oxygen we breathe. Perhaps most obvious is the global seafood harvest totalling over 100 Mt yr–1 (82 and 20 Mt in 2008 for capture and aquaculture, respectively; FAO 2009) from fishing effort that expands more broadly and deeper each year as fishery stocks are depleted (Pauly et al. 2003). Less apparent ecosystem services linked closely to biodiversity and ecosystem function are waste processing and improved water quality, elemental cycling, shoreline protection, recreational opportunities, and aesthetic or educational experiences (Cooley et al. 2009). There is growing concern that ocean acidification caused by fossil fuel emissions, in concert with the effects of other human activities, will cause significant changes in the biodiversity and function of marine ecosystems, with important consequences for resources and services that are important to society. Will the effects of ocean acidification on ecosystems be similar to those arising from other environmental perturbations observed during human or earth history? Although changes in biodiversity and ecosystem function due to ocean acidification have not yet been widely observed, their onset may be difficult to detect amidst the variability associated with other human and non-human factors, and the greatest impacts are expected to occur as acidification intensifies through this century. In theory, large and rapid environmental changes are expected to decrease the stability and productivity of ecosystems due to a reduction in biodiversity caused by the loss of sensitive species that play important roles in energy flow (i.e. food web function) or other processes (e.g. ecosystem engineers; Cardinale et al. 2006). In practice, however, most research concerning the biological effects of ocean acidification has focused on aspects of the performance and survival of individual species during short-term studies, assuming that a change in individual performance will influence ecosystem function.


Author(s):  
Monica Turner ◽  
William Romme ◽  
Daniel Tinker

Our studies following the 1988 Yellowstone fires demonstrated that succession was surprisingly more variable in space and time than even current theory would have suggested, and that initial spatial patterns of disturbance may persist to produce long­lasting changes in vegetation. Our focus now is on explaining the spatial and temporal patterns of succession and understanding how these patterns influence ecosystem function. The most interesting new questions revolve around the degree to which the spatial variation in postfire vegetation -- in particular, the six orders of magnitude variation in pine sapling density, ranging from 0 to greater than 500,000 saplings/ha --controls the spatial variability in ecosystem processes across the landscape.


Author(s):  
David G Delaney ◽  
Lida T Teneva ◽  
Kostantinos A Stamoulis ◽  
Jonatha L Giddens ◽  
Haruko Koike ◽  
...  

Sustainable fisheries management is key to restoring and maintaining ecological function and benefits to people, but it requires accurate information about patterns in resource use, particularly fishing pressure. In most coral reef fisheries and other data-poor contexts, obtaining such information is challenging and remains an impediment to effective management. We developed the most comprehensive regional view of shore-based fishing effort and catch for the Hawaiian Islands to show detailed fishing patterns from across the main Hawaiian Islands (MHI). We reveal these regional patterns through fisher “creel” surveys conducted through collaborative efforts by local communities, state agencies, academics, and environmental organizations, at 18 sites and comprising >10,000 hr of monitoring across a range of habitats and human influences throughout the MHI. Here, we document spatial patterns in nearshore fisheries catch, effort, catch rates (i.e., catch-per-unit-effort [CPUE]), and catch disposition (i.e., use of fish after catch is landed). Line fishing was consistently the most commonly employed gear type (94%), followed by net fishing. The most efficient gear types (i.e., higher CPUE) were spear (0.64 kg hr-1), followed closely by net (0.61 kg hr-1), with CPUE for line (0.16 kg hr-1) 3.9 times lower than spear and 3.7 times lower than net. Creel surveys also reveal rampant illegal fishing activity across the studied locations. Surprisingly, overall, most of the catch was not sold, but rather retained for home consumption or given away to extended family, which indicates that cultural and food security may be stronger drivers of fishing effort than commercial exploitation for nearshore coral reef fisheries in Hawai‘i. Increased monitoring of spatial patterns in nearshore fisheries can inform targeted management, in order to maintain these fisheries for local communities’ food security, cultural, and ecological value.


Author(s):  
Monica Turner ◽  
William Romme ◽  
Daniel Tinker

Our studies following the 1988 Yellowstone fires demonstrated that succession was surprisingly more variable in space and time than even current theory would have suggested, and that initial spatial patterns of disturbance may persist to produce long­lasting changes in vegetation. Our focus now is on explaining the spatial and temporal patterns of succession and understanding how these patterns influence ecosystem function. The most interesting new questions revolve around the degree to which the spatial variation in postfire vegetation in particular, the six orders of magnitude variation in pine sapling density, ranging from 0 to greater than 500,000 saplings/ha controls the spatial variability in ecosystem processes across the landscape. In our current research, we are conducting studies in both Grand Teton and Yellowstone National Parks to answer four major questions:


Author(s):  
Monica Turner ◽  
William Romme ◽  
Daniel Tinker

Our studies following the 1988 Yellowstone flres demonstrated that succession was surprisingly more variable in space and time than even current theory would have suggested, and that initial spatial patterns of disturbance may persist to produce long­ lasting changes in vegetation. Our focus now is on explaining the spatial and temporal patterns of succession and understanding how these patterns influence ecosystem function. The most interesting new questions revolve around the degree to which the spatial variation in postfue vegetation in particular, the six orders of magnitude variation in pine sapling density, ranging from 0 to greater than 500,000 saplings/ha controls the spatial variability in ecosystem processes across the landscape. In our current research, we are conducting studies in both Grand Teton and Yellowstone National Parks to answer four major questions:


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4089 ◽  
Author(s):  
David G. Delaney ◽  
Lida T. Teneva ◽  
Kostantinos A. Stamoulis ◽  
Jonatha L. Giddens ◽  
Haruko Koike ◽  
...  

Sustainable fisheries management is key to restoring and maintaining ecological function and benefits to people, but it requires accurate information about patterns of resource use, particularly fishing pressure. In most coral reef fisheries and other data-poor contexts, obtaining such information is challenging and remains an impediment to effective management. We developed the most comprehensive regional view of shore-based fishing effort and catch published to date, to show detailed fishing patterns from across the main Hawaiian Islands (MHI). We reveal these regional patterns through fisher “creel” surveys conducted by local communities, state agencies, academics, and/or environmental organizations, at 18 sites, comprising >10,000 h of monitoring across a range of habitats and human influences throughout the MHI. All creel surveys included in this study except for one were previously published in some form (peer-reviewed articles or gray literature reports). Here, we synthesize these studies to document spatial patterns in nearshore fisheries catch, effort, catch rates (i.e., catch-per-unit-effort (CPUE)), and catch disposition (i.e., use of fish after catch is landed). This effort provides for a description of general regional patterns based on these location-specific studies. Line fishing was by far the dominant gear type employed. The most efficient gear (i.e., highest CPUE) was spear (0.64 kg h−1), followed closely by net (0.61 kg h−1), with CPUE for line (0.16 kg h−1) substantially lower than the other two methods. Creel surveys also documented illegal fishing activity across the studied locations, although these activities were not consistent across sites. Overall, most of the catch was not sold, but rather retained for home consumption or given away to extended family, which suggests that cultural practices and food security may be stronger drivers of fishing effort than commercial exploitation for coral reef fisheries in Hawai‘i. Increased monitoring of spatial patterns in nearshore fisheries can inform targeted management, and can help communities develop a more informed understanding of the drivers of marine resource harvest and the state of the resources, in order to maintain these fisheries for food security, cultural practices, and ecological value.


2009 ◽  
Vol 66 (5) ◽  
pp. 886-901 ◽  
Author(s):  
S. P. R. Greenstreet ◽  
G. J. Holland ◽  
T. W. K. Fraser ◽  
V. J. Allen

Abstract Greenstreet, S. P. R., Holland, G. J., Fraser, T. W. K., and Allen, V. J. 2009. Modelling demersal fishing effort based on landings and days absence from port, to generate indicators of “activity”. – ICES Journal of Marine Science, 66: 886–901. For many components of marine ecosystems, the derivation of biologically significant, operational “pressure” indicators will rely on modelling fishing mortality from indicators of anthropogenic “activity”. This essentially expands the well established Pressure–State–Response framework to one of Activity–Pressure–State–Response. Within the Common Fisheries Policy, the reporting of fishing effort data, the basic indicator of activity, is not mandatory. A modelling approach is therefore developed that utilizes the data that fishers are obliged to report (days absence from port, landings from each rectangle fished, and the gear used) to provide modelled estimates of fishing effort. The model is parameterized for the Scottish demersal fishing fleet using data collected through the Scottish discards observer scheme, and fishing effort over the period 1997–2004 is modelled. Reported effort data for the period 1960–1998 allowed validation of the model through direct comparison of modelled with reported data in 1997 and 1998. Combining the modelled and reported datasets revealed that Scottish fishing activity levels, remarkably constant over four decades, had declined markedly since 2000. Temporal trends in UK quotas for the main targeted demersal species are considered to assess the effectiveness of catch limitation management as a means of regulating fishing activity. Spatial patterns in effort by the four main gear types used by the Scottish demersal fleet are described, and in general terms, these have changed little over the period 1960–2004. However, distinct spatial patterns emerged in the temporal trends in each ICES rectangle, associated with the recent overall decline in Scottish demersal fishing activity. These patterns were not intuitive, and the implications of this for an ecosystem approach to management are discussed.


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