Case Study: Blue and Mako Shark Catch Rates in US Atlantic Recreational Fisheries as Potential Indices of Abundance

2009 ◽  
pp. 205-212 ◽  
Author(s):  
Gregory Skomal ◽  
Elizabeth A. Babcock ◽  
Ellen K. Pikitch
Keyword(s):  
Recreational Fisheries ◽  
Mako Shark ◽  
Catch Rates

scholarly journals Bycatch: complementary information for understanding fish behaviour. Namibian Cape hake (M. capensis and M. paradoxus) as a case study

2006 ◽  
Vol 63 (8) ◽  
pp. 1513-1519 ◽  
Author(s):  
Ana Gordoa ◽  
Heinrich Lesch ◽  
Silvia Rodergas
Keyword(s):  
Negative Relationship ◽  
Temporal Distribution ◽  
Horse Mackerel ◽  
Sample Data ◽  
Strong Negative Relationship ◽  
Different Depths ◽  
Spatio Temporal ◽  
Catch Rates ◽  
Informative Component

Abstract To identify spatio-temporal distribution in Namibian Cape hake (M. paradoxus and M. capensis), incidental hake catch by the horse mackerel fleet and targeted catch by the hake fleet were analysed for the period 1999–2004. The targeted catch, 45 955 fishing days, came from hake fishery logbooks and the incidental catch, 24 689 trawls, from observers' sample data collected aboard vessels of the horse mackerel fleet. A strong negative relationship between monthly catch rates (cpue) and bycatch was observed, confirming that the seasonal change in catchability is caused by differences in hake vertical dispersion. The October trends were an exception: both cpue and bycatch were negative. A drop in catchability at different depths of the fishing grounds indicates that M. capensis migrates to shallower water (<200 m) at the peak of spawning. Although there was no significant relationship between annual catch rates and bycatch, probably because of the short length of the time-series, annual bycatch should not be discarded as an indicator of hake recruitment. The results highlight the potential informative component of bycatch in identifying population patterns that cannot be extracted from the targeted catch.

Experimental demonstration of catch hyperstability from habitat aggregation, not effort sorting, in a recreational fishery

2020 ◽  
Vol 77 (4) ◽  
pp. 762-769 ◽  
Author(s):  
Colin J. Dassow ◽  
Alexander J. Ross ◽  
Olaf P. Jensen ◽  
Greg G. Sass ◽  
Brett T. van Poorten ◽  
...  
Keyword(s):  
Littoral Zone ◽  
Habitat Preferences ◽  
Fish Abundance ◽  
Experimental Demonstration ◽  
Recreational Fisheries ◽  
Spawning Habitat ◽  
Preferred Habitat ◽  
Fish Aggregation ◽  
Catch Rates ◽  
The Relationship

The relationship between angler catch rates and fish abundance can contribute to or hinder sustainable exploitation of fisheries depending on whether catch rates are proportional to fish abundance or are hyperstable. We performed a whole-ecosystem experiment in which fish abundance was manipulated and paired with weekly angler catch rate estimates from controlled experimental fishing. Catch rates were hyperstable (β = 0.47) in response to changes in fish abundance. By excluding effort sorting (i.e., catch rates remaining high because less skilled anglers leave the fishery as abundance declines), our experiment isolated the influence of fish aggregation as a driver of hyperstability. Spatial analysis of catch locations did not identify clustering around specific points, suggesting that loose aggregation to preferred habitat at the scale of the entire littoral zone was enough to maintain stable catch rates. In our study, general, non-spawning, habitat preferences created loose aggregations for anglers to target, which was sufficient to generate hyperstability. Habitat preferences are common to nearly all fishes and widely known to anglers, suggesting that many harvest-oriented recreational fisheries can be expected to exhibit hyperstability.

Biosocioeconomic analysis of marine recreational fisheries: A comparative case study from the Eastern Mediterranean, Turkey

2016 ◽  
Vol 174 ◽  
pp. 270-279 ◽  
Author(s):  
Sezgin Tunca ◽  
Vahdet Ünal ◽  
Bülent Miran ◽  
Harun Güçlüsoy ◽  
Ana Gordoa
Keyword(s):  
Eastern Mediterranean ◽  
Comparative Case Study ◽  
Recreational Fisheries

scholarly journals Fishing for euros: how mapping applications can assist in maintaining revenues under the Landing Obligation

2020 ◽  
Author(s):  
Julia Calderwood ◽  
Kristian Schreiber Plet-Hansen ◽  
Clara Ulrich ◽  
David G Reid
Keyword(s):  
Temporal Dynamics ◽  
Species Distributions ◽  
Fishing Effort ◽  
Fishing Industry ◽  
Fishing Activity ◽  
Spatio Temporal ◽  
Catch Rates ◽  
Demersal Species ◽  
High Catch

Abstract With the introduction of the Landing Obligation (LO) in EU fisheries, there is an increasing need for fishers to avoid unwanted catches while maximizing revenues. Improving understanding of the spatio-temporal dynamics of unwanted catches could assist the fishing industry optimize catches by altering where they fish. How following such advice relates to revenues and fishery dynamics requires more consideration. We take an existing hotspot mapping methodology and examine how it could be used to identify fishing opportunities under the LO in Irish (Celtic Sea) and Danish (North Sea and Skagerrak) demersal fisheries. We consider if fishing effort can be relocated to avoid unwanted catches while maintaining revenues. The value per unit effort of fishing activity in both areas was often linked to high catch rates of key demersal species (cod, haddock, hake, and whiting). Our analyses indicated, however, that there are options to fish in areas that could provide higher revenues while avoiding below minimum conservation reference size catches and choke species. This was evident across both case study areas demonstrating that hotspot mapping tools could have wide applicability. There does, however, remain a need to explore how the displacement of vessels may further alter species distributions and fleet economics.

Model selection and multimodel inference for standardizing catch rates of bycatch species: a case study of oceanic whitetip shark in the Hawaii-based longline fishery

2013 ◽  
Vol 70 (12) ◽  
pp. 1723-1740 ◽  
Author(s):  
Jon Brodziak ◽  
William A. Walsh
Keyword(s):  
Model Selection ◽  
Negative Binomial ◽  
Longline Fishery ◽  
Catch Per Unit Effort ◽  
Multimodel Inference ◽  
Stepwise Variable Selection ◽  
Alternative Hypotheses ◽  
Pelagic Longline Fishery ◽  
Catch Rates

One key issue for standardizing catch per unit effort (CPUE) of bycatch species is how to model observations of zero catch per fishing operation. Typically, the fraction of zero catches is high, and catch counts may be overdispersed. In this study, we develop a model selection and multimodel inference approach to standardize CPUE in a case study of oceanic whitetip shark (Carcharhinus longimanus) bycatch in the Hawaii-based pelagic longline fishery. Alternative hypotheses for shark catch per longline set were characterized by the variance to mean ratio of the count distribution. Zero-inflated and non-inflated Poisson, negative binomial, and delta-gamma models were fit to fishery observer data using stepwise variable selection. Alternative hypotheses were compared using multimodel inference. Results from the best-fitting zero-inflated negative binomial model showed that standardized CPUE of oceanic whitetip sharks decreased by about 90% during 1995–2010 because of increased zero catch sets and decreased CPUE on sets with positive catch. Our model selection approach provides an objective way to address the question of how to treat zero catches when analyzing bycatch CPUE.

Development of a small-scale commercial fish farm in the Ashanti Region of Ghana: a case study of Mr. Poku Gyinaye of Bosomtwi Integrated Aqualife Village.

2020 ◽  
Author(s):  
Nelson Agbo
Keyword(s):  
Management Practices ◽  
Clarias Gariepinus ◽  
Fish Farm ◽  
Small Scale ◽  
Recreational Fisheries ◽  
Commercial Fish ◽  
Ashanti Region ◽  
Public Aquarium ◽  
Predatory Fishes

Abstract This case study documents the development of a small-scale fish farm in an attempt to highlight the efforts of a fish farmer (Mr. Poku Gyinaye, a former Fisheries officer) to establish a commercial fish farm in the Ashanti Region of Ghana. Accounts of the facilities, technology and management practices used by the farmer are described as well as his profile. The objectives of the farmer to undertake such a project were to produce fish seed for fish farmers to help them improve fish production, provide practical aquaculture training for prospective fish farmers and access to recreational fisheries for both local and foreign tourists. At the time of writing (by May 2009), Mr. Gyinaye has almost completed setting up the hatchery and has three large ponds for recreational fishing. He also has plans to start a public aquarium on the site. The main activities on his farm centre on Oreochromis niloticus and Clarias gariepinus fingerling production. He intends to stock his recreational ponds with indigenous predatory fishes.

scholarly journals Using Harvest Slot Limits to Promote Stock Recovery and Broaden Age Structure in Marine Recreational Fisheries: A Case Study

2020 ◽  
Vol 40 (6) ◽  
pp. 1451-1471
Author(s):  
Jacob M. Kasper ◽  
Jeffrey Brust ◽  
Amanda Caskenette ◽  
Jason McNamee ◽  
Jason C. Vokoun ◽  
...  
Keyword(s):  
Age Structure ◽  
Recreational Fisheries ◽  
Stock Recovery

Comparing indicators of recreational fishing in Port Phillip Bay, Australia, from 2008 to 2011 with variability from a background period (2003–07)

2019 ◽  
Vol 70 (10) ◽  
pp. 1345 ◽  
Author(s):  
Karina L. Ryan ◽  
Simon C. Conron
Keyword(s):  
Time Series Data ◽  
Series Data ◽  
Recreational Fishing ◽  
Commercial Fisheries ◽  
Recreational Fisheries ◽  
Similar Time ◽  
Frequency Distributions ◽  
Background Period ◽  
Catch Rates ◽  
Resource Status

Understanding the effects of anthropogenic disturbances on marine environments that support recreational fisheries requires suitable monitoring data. Although catch rates are frequently considered to inform resource status for commercial fisheries, similar time series data are generally unavailable for recreational fisheries. This study is based on 9 years of data from boat-based recreational fishing surveys in Port Phillip Bay, Australia. Harvest rates and length distributions of the retained catches for three target species were statistically compared over 4 years following commencement of shipping channel dredging (2008–11) with variability from a background period (2003–07). Mean harvest rates were generally within historical ranges, with increases for snapper (Chrysophrys auratus) and King George whiting (Sillaginodes punctatus) and decreases for sand flathead (Platycephalus bassensis). Length–frequency distributions were not significantly different to the background period, except for increased mean length of snapper and King George whiting in 2011. This study demonstrates that data obtained from sampling recreational fishers can provide valuable information to monitor harvested resources and maintain social amenity for recreational fisheries during periods of anthropogenic disturbance. Trends in harvest rates from recreational fishing surveys may also complement catch rates from commercial fisheries for assessments of multisector fisheries or stand-alone assessments for recreational-only fisheries.

Effectively managing angler satisfaction in recreational fisheries requires understanding the fish species and the anglers

2015 ◽  
Vol 72 (4) ◽  
pp. 500-513 ◽  
Author(s):  
Ben Beardmore ◽  
Len M. Hunt ◽  
Wolfgang Haider ◽  
Malte Dorow ◽  
Robert Arlinghaus
Keyword(s):  
Fish Species ◽  
Negative Influence ◽  
Catch Rate ◽  
Relative Importance ◽  
Recreational Fisheries ◽  
Northern Germany ◽  
By Catch ◽  
Catch Rates ◽  
High Catch ◽  
Important Objective

Whenever satisfied anglers are an important objective of recreational fisheries management, understanding how trip outcomes influence satisfaction reports is critical. While anglers, generally, prefer high catch rates and large fish, the relative importance of these catch outcomes for catch satisfaction has not been established across species and angler types. We examined relationships between angler specialization, trip outcomes (both catch and non-catch characteristics such as crowding), and catch satisfaction across six freshwater fish species in northern Germany. As expected, catch satisfaction was primarily determined by catch rate and fish size in all fish species; however, the relative importance of these two outcomes varied considerably across species and among angler types that differed by commitment to fishing. We found a diminishing marginal return of satisfaction for increasing catch rate for all but small-bodied cyprinid species, while increasing size of largest retained fish monotonically increased catch satisfaction in all species we examined. Non-catch outcomes (e.g., the number of other anglers seen while fishing) also had a significant negative influence on catch satisfaction, suggesting that non-catch factors are important in establishing expectations and for contextual evaluation of catch outcomes. We also determined that diversified trips made anglers more satisfied and that all else being equal, specialized anglers increased catch satisfaction from travel and fishing time. The results highlight the importance for managers to consider their particular mix of anglers as well as the fish species present when setting regulations aimed at increasing angler satisfaction.

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