5 research outputs found
Movement patterns of Lichia amia (Teleostei: Carangidae): results from a long-term cooperative tagging project in South Africa
Understanding fish movement patterns and migrations is important for fisheries management as well as the identification and conservation of critical habitats. Data collected by the Oceanographic Research Institute’s Cooperative Fish Tagging Project (ORI-CFTP) were used to describe the large-scale movement patterns of Lichia amia along the South African coastline. A total of 10 762 L. amia were tagged between 1984 and 2012, of which 744 (7%) were recaptured. Most tagging effort, mainly on juvenile and subadult individuals, took place along the south-eastern (i.e. Eastern Cape) and south-western (i.e. Western Cape) regions of the country during summer. Conversely, more L. amia were tagged and recaptured (mostly adults) during winter and spring (July to November) along the north-east coast (i.e. KwaZulu-Natal). Movements (dispersal distance in kilometres) by juveniles were restricted and largely confined to estuaries within the south-eastern and south-western regions of the country. There was a significant effect of fish size on distance moved (ANOVA: p < 0.001), with evidence of a distinct seasonal (winter) longshore migration by adults to KwaZulu-Natal. The consequences of juvenile residency in estuarine habitats and high recapture rate of adults during a directed, seasonal spawning migration are discussed in light of improving current fisheries management.Keywords: fisheries management, leervis, migration, movement behaviour, tag recaptur
Movement patterns of Lichia amia (Teleostei Carangidae) results from a long-term cooperative tagging project in South Africa
Understanding fish movement patterns and migrations is important for fisheries management as well as the identification and conservation of critical habitats. Data collected by the Oceanographic Research Institute's Cooperative Fish Tagging Project (ORI-CFTP) were used to describe the large-scale movement patterns of Lichia amia along the South African coastline. A total of 10 762 L. amia were tagged between 1984 and 2012, of which 744 (7%) were recaptured. Most tagging effort, mainly on juvenile and subadult individuals, took place along the south-eastern (i.e. Eastern Cape) and south-western (i.e. Western Cape) regions of the country during summer. Conversely, more L. amia were tagged and recaptured (mostly adults) during winter and spring (July to November) along the north-east coast (i.e. KwaZulu-Natal). Movements (dispersal distance in kilometres) by juveniles were restricted and largely confined to estuaries within the south-eastern and south-western regions of the country. There was a significant effect of fish size on distance moved (ANOVA: p0.001), with evidence of a distinct seasonal (winter) longshore migration by adults to KwaZulu-Natal. The consequences of juvenile residency in estuarine habitats and high recapture rate of adults during a directed, seasonal spawning migration are discussed in light of improving current fisheries management
Spiny lobster recreational fisheries in Australia and New Zealand: An overview of regulations, monitoring, assessment and management
Spiny (rock) lobsters occur globally and, although harvest is dominated by commercial fisheries, it is important to account for recreational harvest in stock assessments and fisheries management. This paper provides a contemporary review of recreational fishing for five spiny lobster species in Australia and New Zealand. Each jurisdiction has established approaches for collecting data which best meet their information needs (telephone-diary or telephone-recall surveys, charter logbooks, tag reporting). Jurisdictions with specific spiny lobster licences (Western Australia, Tasmania) or mandatory reporting (charter logbooks in Western Australia, tag reporting in Victoria) use these registers as a sampling frame for annual reporting of participation, fishing effort, catch (numbers) and harvest (tonnes). All other jurisdictions use a general fishing licence or general population sampling frame for telephone-diary surveys to provide periodic reporting of catch and harvest. Annual participation in spiny lobster recreational fishing was highest in Western Australia (35,236 ± SE 626 fishers in 2022–23), followed by Tasmania (13,715 ± SE 1067 fishers in 2022–23) and Victoria (5516 fishers in 2020–21). Annual recreational harvest of all spiny lobster species, combined for the most recent data collection period in each jurisdiction, was 830 tonnes; consisting mostly of Western Rock Lobster (Panulirus cygnus) from Western Australia and Southern Rock Lobster (Jasus edwardsii) from Tasmania and New Zealand. This review illustrates the various spatial scales of monitoring, reporting and assessment in each jurisdiction. All monitoring provides information on catch and harvest, with some also reporting participation, effort, carapace length and non-catch related variables. The designs underlying these approaches vary from probability-based (opt-out) and census (mandatory), and it is important to understand the benefits and inherent biases of each. Understanding the parallels between jurisdictions offers valuable insights into how to cost-effectively monitor spiny lobster recreational fisheries and integrate this data into stock assessment and harvest strategies to support sustainable fisheries into the future
Directed conservation of the world's reef sharks and rays
Many shark populations are in decline around the world, with severe ecological and economic consequences. Fisheries management and marine protected areas (MPAs) have both been heralded as solutions. However, the effectiveness of MPAs alone is questionable, particularly for globally threatened sharks and rays (‘elasmobranchs’), with little known about how fisheries management and MPAs interact to conserve these species. Here we use a dedicated global survey of coral reef elasmobranchs to assess 66 fully protected areas embedded within a range of fisheries management regimes across 36 countries. We show that conservation benefits were primarily for reef-associated sharks, which were twice as abundant in fully protected areas compared with areas open to fishing. Conservation benefits were greatest in large protected areas that incorporate distinct reefs. However, the same benefits were not evident for rays or wide-ranging sharks that are both economically and ecologically important while also threatened with extinction. We show that conservation benefits from fully protected areas are close to doubled when embedded within areas of effective fisheries management, highlighting the importance of a mixed management approach of both effective fisheries management and well-designed fully protected areas to conserve tropical elasmobranch assemblages globally
Widespread diversity deficits of coral reef sharks and rays
A global survey of coral reefs reveals that overfishing is driving resident shark species toward extinction, causing diversity deficits in reef elasmobranch (shark and ray) assemblages. Our species-level analysis revealed global declines of 60 to 73% for five common resident reef shark species and that individual shark species were not detected at 34 to 47% of surveyed reefs. As reefs become more shark-depleted, rays begin to dominate assemblages. Shark-dominated assemblages persist in wealthy nations with strong governance and in highly protected areas, whereas poverty, weak governance, and a lack of shark management are associated with depauperate assemblages mainly composed of rays. Without action to address these diversity deficits, loss of ecological function and ecosystem services will increasingly affect human communities