Monitoring the recreational gamefish fishery off south-eastern Australia

2003 ◽  
Vol 54 (4) ◽  
pp. 425 ◽  
Author(s):  
Michael Lowry ◽  
Jeff Murphy
Keyword(s):  
Spatial Distribution ◽  
Monitoring Program ◽  
Fishing Effort ◽  
Target Species ◽  
Eastern Australia ◽  
Species Groups ◽  
Catch Rates ◽  
Catch Composition ◽  
The Impact ◽  
Integrated Program

The east coast Australian gamefish fishery is a diverse, multi-species fishery that targets billfish, sharks, tuna and other pelagic fish along the east Australian seaboard. A Gamefish Tournament Monitoring Program (GTMP) was undertaken, and 39021 angler trips from 1996 to 2000 were analysed. The program reports on trends in fishing effort, catch rates, catch composition, proportions of captures tagged and released and spatial distribution of catches for the principal recreational billfish species: black marlin (Makaira indica), striped marlin (Tetrapterus audax) and blue marlin (Makiara nigricans).The GTMP was principally designed as part of an integrated program to monitor the recreational gamefish fishery. The spatial and temporal design of the program restricted statistical analyses however, there were trends in fishing effort, directed effort, catch rates, catch composition, proportions of fish tagged and spatial distribution of catches for the principal recreational billfish species over seven successive years (1994–2000). Analysis of catch data, stratified by directed effort, indicated significant differences in catches of target species, demonstrating the importance of calculating catch rate estimates according to the main target preference. Analysis of tournament based tagging information indicated that while overall tournament tagging rates remained high (88%) there were significant differences in the number of fish tagged between species groups highlighting the impact that angler attitude and the competition point score structure has on the harvest of gamefish target species.

Fish and invertebrate by-catch in the crab pot fishery in the Isle of Man, Irish Sea

2017 ◽  
Vol 98 (8) ◽  
pp. 2099-2111
Author(s):  
Fikret Öndes ◽  
Michel J. Kaiser ◽  
Lee G. Murray
Keyword(s):  
Irish Sea ◽  
Target Species ◽  
Catch Per Unit Effort ◽  
Isle Of Man ◽  
Ecosystem Effects ◽  
By Catch ◽  
Catch Rates ◽  
Taxonomic Groups ◽  
Catch Composition ◽  
Autumn And Winter

Baited trap or pot fisheries are considered to have relatively few wider ecosystem effects on the marine environment, particularly when compared with towed mobile fishing gear. However, this assumption is rarely tested in the field. This study aimed to determine the composition of non-target species that occur in crustacean pots and to assess spatial and temporal differences in catches in the waters around the Isle of Man, Irish Sea. The data were collected using fishery independent surveys and a questionnaire study. Based on fishery independent surveys, a total of five taxonomic groups and 43 species occurred as by-catch. The dominant by-catch species was velvet crab Necora puber. The by-catch per unit effort (BPUE) for all of the non-target species was low particularly in comparison to towed bottom gear fisheries around the Isle of Man. BPUE of species composition varied considerably between different locations around the Isle of Man. The results of both the fishery independent and questionnaire data suggested that the by-catch rates varied with season with peak BPUE occurring in spring which then declined into autumn and winter. By-catch composition did not decrease significantly with an increasing target species catch. Overall, by-catch was low relative to target species catch which may be partially attributable to the use of escape panels in pot fisheries in the Isle of Man.

scholarly journals Estimating efficiency of survey and commercial trawl gears from comparisons of catch-ratios

2017 ◽  
Vol 74 (5) ◽  
pp. 1448-1457 ◽  
Author(s):  
Nicola D. Walker ◽  
David L. Maxwell ◽  
Will J. F. Le Quesne ◽  
Simon Jennings
Keyword(s):  
Monitoring Program ◽  
Data File ◽  
Species Group ◽  
Additive Models ◽  
Reference Points ◽  
Target Species ◽  
Commercial Catch ◽  
The North ◽  
Gear Efficiency ◽  
Species Groups

Abstract Assumptions about gear efficiency and catchability influence estimates of abundance, mortality, reference points and catch potential. Despite the need to better quantify fishing effects on some target species and on many non-target species taken as bycatch, there are few gear efficiency estimates for some of the most widely deployed towed fishing gears in the northeast Atlantic. Here, we develop a method that applies generalised additive models to catch-at-length data from trawl surveys and a commercial catch and discard monitoring program in the North Sea to estimate catch-ratios. We then rescale these catch-ratios and fit relationships to estimate gear efficiency. When catches of individuals by species were too low to enable species-specific estimates, gear efficiency was estimated for species-groups. Gear efficiency (and associated uncertainty) at length was ultimately estimated for 75 species, seven species-groups and for up to six types of trawl gear per species or species-group. Results are illustrated for dab (Limanda limanda), grey gurnard (Eutrigula gurnardus) and thornback ray (Raja clavata), two common non-target species and a depleted elasmobranch. All estimates of gear efficiency and uncertainty, by length, species, species-group and gear, are made available in a supplementary data file.

scholarly journals Effect of hook and bait type on catch per unit effort in the Aegean Sea demersal longline fishery

2021 ◽  
Vol 38 (2) ◽  
pp. 181-188
Author(s):  
Ozan Soykan ◽  
Cemil Sağlam ◽  
İlker Aydın ◽  
Hasan Tuncay Kınacıgil
Keyword(s):  
Sparus Aurata ◽  
Length Distribution ◽  
Aegean Sea ◽  
Fishing Effort ◽  
Longline Fishery ◽  
Total Catch ◽  
Catch Per Unit Effort ◽  
Unit Effort ◽  
Catch Composition ◽  
The Impact

This study aimed to determine the impact of hook and bait type on the catch composition and catch per unit effort. Effects of hook and bait types on catch composition, catch per unit effort (CPUE), length and weight distributions in demersal longline fishery were determined by experimental surveys on demersal longline sets in the Aegean Sea. A total of 12 samplings corresponding to 4800 hook fishing effort were performed between April 2014 and September 2014. Two bait types; sardine (Sardina pilchardus) and grooved razor shell (Solen marginatus) and two hook types; J-hook and C-hook were tested. CPUE values were calculated for each species and assessed between different hook-bait combinations. A total of 623 individuals were captured belonging to 3 families and 9 species. It was found that more than 60% of total catch was captured by grooved razor shell and more than 50% of the total catch was caught with J type hook. J hook was found to be close to significant (p=0.06) and grooved razor shell was found significant (p=0.02) for CPUE. The effect of bait type was found to be more significant than that of hook type for CPUE and length distribution. Hook-bait combination differed according to species and C hook baited with sardine was determined to be the best combination for Sparus aurata as the most targeted fish in the study area. Discard ratio was calculated to be 34% in terms of weight and 42.5% in terms of total number of individuals for pooled data. The condition value (K) of the species ranged from 1.05 to 1.68 and differed according to bait type. Most of the high commercial value species caught with any hook-bait combination experimented within this study are larger than minimum fishing length according to minimum landing size regulations of Turkish fishery and maturity studies.

Likely impacts of an eastward expansion of the inshore gill-net fishery in the Western Cape, South Africa: implications for management

2003 ◽  
Vol 54 (1) ◽  
pp. 39 ◽  
Author(s):  
K. Hutchings ◽  
S. J. Lamberth
Keyword(s):  
West Coast ◽  
Fishing Effort ◽  
Western Cape ◽  
Catch Per Unit Effort ◽  
South West ◽  
Gill Net ◽  
South West Coast ◽  
By Catch ◽  
Catch Rates ◽  
The Impact

Current South African government policy aims to create more equitable access to marine resources and there is pressure to increase the inshore gill-net fishing effort. At present, the gill-net fishery in the Western Cape is confined to the cool temperate west coast. In order to ascertain the potential catch if the fishery was to expand along the warm temperate south-west coast, a program of experimental netting was conducted. Estuarine and coastal marine sites were sampled bimonthly, using a range of commercial gill-nets (44–178 mm stretch-mesh). Although the target species, Liza richardsonii, dominated the catches, at least 33 of the by-catch species caught were also targeted by the commercial or recreational line-fish sectors. The number of species captured and the line-fish (by-catch) catch per unit effort (CPUE) were greatest in areas currently closed to the commercial gill-net fishery. Multivariate analysis indicated significant differences in catch rates and composition between exploited west coast and unexploited south-west coast sites. A combination of natural biogeographical trends and the impact of over 100 years of commercial gill-netting on the west coast are the likely causes of these differences. A spatial expansion of the gill-net fishery could have a detrimental impact on overexploited line-fish stocks and lead to increased user conflict.

Yield-per-recruit analysis of Eastern King Prawns Penaeus plebejus Hess, in Eastern Australia

1990 ◽  
Vol 41 (1) ◽  
pp. 175 ◽  
Author(s):  
JP Glaister ◽  
SS Montgomery ◽  
VC McDonall
Keyword(s):  
Fishing Effort ◽  
Commercial Catch ◽  
Eastern Australia ◽  
The Difference ◽  
Time Lagged ◽  
Catch Composition ◽  
Catch Per Effort ◽  
Yield Per Recruit ◽  
The Relationship ◽  
Mortality Estimates

The eastern king prawn, P. plebejus, has been commercially exploited for over 50 years. Controversy has arisen over the presumed effect of increasing fishing effort on reported declining catch per vessel and the need for further management of the fishery. The present study develops the information necessary to evaluate this presumption by analysing landing statistics, data developed from a log-book programme, commercial catch composition and data from a series of mark-recapture experiments conducted on part of the fishing grounds. Population parameters (growth, mortalities and other losses) were calculated via a series of tagging experiments. Recapture rates of tagged prawns were examined for each point release (local recapture) and for the state as a whole (sequentially applied effort), the difference providing estimates of emigration rate. Weekly values chosen for these parameters allowed calculation of yield-per-recruit estimates. For 1979 and 1980, respectively, fishing mortality estimates ranged between 0.04 and 0.08 per week, depending upon number of vessels per port; emigration was estimated to be 0.13 and 0.18 per week for the two years, tagging mortality (0.08 per week), and all other losses other than by tagging and emigration at 0.06 and 0.08 per week. A compartmented, time-lagged model of the fishery was used to predict changes in yield per recruit as a consequence of changes in management strategy and to describe the relationship between fishing effort and yield per recruit. The analyses suggested that limited benefits in terms of yield per recruit would eventuate from substantial increases in effort but that substantial decreases in catch per effort were likely.

Evaluating empirical indicators and reference points for fisheries management: application to the broadbill swordfish fishery off eastern Australia

2001 ◽  
Vol 52 (6) ◽  
pp. 819 ◽  
Author(s):  
André E. Punt ◽  
Robert A. Campbell ◽  
Anthony D. M. Smith
Keyword(s):  
Length Distribution ◽  
Fishing Effort ◽  
Reference Points ◽  
Current Status ◽  
Stock Structure ◽  
Eastern Australia ◽  
Stock Assessments ◽  
Management Application ◽  
The Mean ◽  
Catch Rates

Calls to use target, limit and threshold reference points to achieve precautionary management goals have increased substantially in recent years. For many fisheries there is little chance of conducting formal stock assessments, and indicators of stock status have to be based on changes in measurable quantities such as catch rates and percentiles of the length distribution of the catch. Use of such empirical indicators for management decisions also requires a choice of appropriate reference or trigger levels for the indicators. Monte Carlo simulation can be used to examine the performance of alternative indicators and associated reference points in terms of their ability to correctly identify the biological conditions that they were designed to measure. This study examines the performance of several potential empirical indicators for broadbill swordfish off eastern Australia, taking into account uncertainties in stock structure, current status, and future trends in fishing effort. Indicators based on catch rates are shown to be potentially very misleading. In contrast, indicators based on the mean length or mean weight of the catch perform better, because these quantities change in a more predictable manner with abundance. Nevertheless, reference points based on these quantities are frequently ‘triggered’ either too early or too late.

Blue and Mako Shark by-catch in the Japanese Longline Fishery off South-eastern Australia

1992 ◽  
Vol 43 (1) ◽  
pp. 227 ◽  
Author(s):  
JD Stevens
Keyword(s):  
Bluefin Tuna ◽  
Fishing Effort ◽  
Adolescent Females ◽  
Actual Number ◽  
Mako Shark ◽  
Shortfin Mako ◽  
Eastern Australia ◽  
Southern Bluefin Tuna ◽  
By Catch ◽  
Catch Rates

During the last 10 years, up to 70 Japanese longline vessels have fished Tasmanian waters of the Australian Fishing Zone each season, targeting bluefin tuna (Thunnus maccoyii). The average seasonal fishing effort in Tasmanian waters is about 3.3 million hooks, and data from observers suggests that, this results in a by-catch of some 34 000 blue sharks (Prionace glauca) each year, representing a weight of about 275 tonnes. In the last few years, fishing effort has increased as the catch rates of southern bluefin tuna have declined. The sharks are discarded after removal of the fins. The actual number of blue sharks hooked is much higher than 34000 because many are released by either shaking or cutting them off the line, although they are often damaged in the process. The majority of blue sharks caught are immature or adolescent females. Smaller numbers of shortfin mako sharks (Isurus oxyrinchus) are also caught and retained both for their fins and their meat. Tasmanian waters represent only one area of the Australian Fishing Zone fished by Japanese longliners.

scholarly journals Diversification insulates fisher catch and revenue in heavily exploited tropical fisheries

2020 ◽  
Vol 6 (8) ◽  
pp. eaaz0587 ◽  
Author(s):  
James P. W. Robinson ◽  
Jan Robinson ◽  
Calvin Gerry ◽  
Rodney Govinden ◽  
Cameron Freshwater ◽  
...  
Keyword(s):  
High Resolution ◽  
Fisheries Management ◽  
Management Strategies ◽  
Fishing Effort ◽  
Marine Resources ◽  
Nutritional Security ◽  
Fishing Vessels ◽  
Species Groups ◽  
Catch Rates ◽  
Average Catch

Declines in commercial landings and increases in fishing fleet power have raised concerns over the continued provisioning of nutritional and economic services by tropical wild fisheries. Yet, because tropical fisheries are often data-poor, mechanisms that might buffer fishers to declines are not understood. This data scarcity undermines fisheries management, making tropical fishing livelihoods particularly vulnerable to changes in marine resources. We use high-resolution fisheries data from Seychelles to understand how fishing strategy (catch diversification) influences catch rates and revenues of individual fishing vessels. We show that average catch weight decreased by 65% over 27 years, with declines in all nine species groups coinciding with increases in fishing effort. However, for individual vessels, catch diversity was associated with larger catches and higher fishing revenues and with slower catch declines from 1990 to 2016. Management strategies should maximize catch diversity in data-poor tropical fisheries to help secure nutritional security while protecting fishing livelihoods.

scholarly journals Rockhopper penguins and other marine life threatened by driftnet fisheries at Tristan da Cunha

Oryx ◽  
1991 ◽  
Vol 25 (2) ◽  
pp. 76-79 ◽  
Author(s):  
Peter G. Ryan ◽  
John Cooper
Keyword(s):  
Atlantic Ocean ◽  
Large Scale ◽  
Fishing Effort ◽  
South Atlantic ◽  
South Atlantic Ocean ◽  
Target Species ◽  
The South ◽  
Tristan Da Cunha ◽  
The Pacific ◽  
The Impact

The oriental driftnet fleet, which is responsible for the large-scale mortality of non-target species in the Pacific Ocean, has extended its range to include the South Atlantic Ocean. Relatively little is known about the areas of operation and impacts of driftnetting in the South Atlantic as yet, but it is emerging that driftnetting is equally devastating to the fauna of this ocean. This paper reviews the impact of the driftnet fishery on non-target species in the central South Atlantic Ocean. Several lines of evidence suggest that fishing effort is focused on Tristan da Cunha, apparently resulting in considerable mortality of rockhopper penguins Eudyptes chrysocome and other marine organisms. Britain should take steps to curb this destructive fishing technique in Tristan waters.

scholarly journals A modelling approach to evaluate the impact of fish spatial behavioural types on fisheries stock assessment

2018 ◽  
Vol 76 (2) ◽  
pp. 489-500 ◽  
Author(s):  
Josep Alós ◽  
Andrea Campos-Candela ◽  
Robert Arlinghaus
Keyword(s):  
Stock Assessment ◽  
Fishing Effort ◽  
Fish Stock ◽  
Catch Per Unit Effort ◽  
Wide Range ◽  
Stock Assessments ◽  
Theoretical Predictions ◽  
Behavioural Types ◽  
Catch Rates ◽  
The Impact

Abstract Spatial behavioural types (SBTs) arise from between-individual differences in behavioural traits that foster spatial behavioural patterns that are consistent over time and ecological contexts. Fish stocks are regularly assessed using catch per unit effort (CPUE) as input data that may non-linearly co-vary with the underlying abundance (N) of the exploited stock when SBT affect catchability. We hypothesized that SBT promote characteristic changes in catchability within harvesting seasons that affect catch rates and in turn catch-based fish stock assessments. To test this hypothesis, we developed a spatially explicit agent-based simulation where we measured encounters between fish and fishers and estimated the shape of the CPUE–N relationship. We ran the simulation in a prototypical fish–fisher encounter-leads-to-catch-type fishery and systematically studied outcomes in the presence or absence of SBTs. It was revealed that the existence of SBTs leads to CPUE inevitably declining faster than N (a process known as hyperdepletion) when compared with a simulation lacking SBTs. This finding was consistent in a wide range of fishing effort scenarios. The emergent hyperdepletion of catch rates was caused by fast and behavioural-selective exploitation of vulnerable SBT that encompassed the mobile component of the fish stock. The theoretical predictions received support from field data from a coastal recreational fishery. Our work suggests that the consideration of SBT when interpreting trends in CPUE data may notably improve stock assessments by providing a more reliable CPUE–N relationship.

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