Literatura académica sobre el tema "Vincent Gulf Region"

The characteristics of movement of the South Australian population of King George whiting (Sillaginodes punctata) were determined through analysis of tag and recapture records collected from three tagging periods: (i) 1968–1969; (ii) 1978–1985; and (iii) 1986–1987. The characteristics were compared between the northern and southern parts of two large fishery regions, and determined for fish tagged at different sizes and ages. Fish tagged in the northern Gulf St Vincent and Spencer Gulf moved southwards up to several hundred kilometres, but those tagged in the southern areas showed no systematic directional displacement. Most fish tagged were subadults or young, immature adults at 2–4 years of age. Small, young fish did not move far until a considerable period after tagging, whereas some fish >300 mm total length (TL) at tagging moved substantial distances within only a few weeks. Fish movement resulted in a significant ontogenetic habitat shift, from relatively protected shallow waters that support extensive meadows of seagrass, to southern, exposed, deeper waters and rocky reef. As a result of this systematic, directional displacement the age structures of the fishery catches also varied systematically throughout the two regions. In the northern areas these were simple and dominated by the 3+ age class, whereas in the south they were complex and consisted of the 2+ to 17+ age classes. Because the latter were the spawning populations, fish movement is an obligate step in the life history that ultimately results in supplementation of numbers on the spawning grounds. The consequences for fishery management are discussed.

Three tasks are usually required to introduce new technologies that reduce by-catches in commercial fisheries: (i) identify and quantify the particular by-catch issue that requires the new devices; (ii) develop and test the devices; and (iii) implement the devices into industry by voluntary acceptance and/or legislation. To solve by-catch problems in prawn-trawl fisheries in three regions of Australia, different approaches have been followed with varying success, and their comparison identifies an ideal framework under which such problems can be resolved.In northern Australia’s prawn-trawl fisheries, the main by-catch issues involved turtles and the discard of a large diversity offish species. To quantify these issues, data were obtained from research vessels, industry logbooks and samples from fishers. Before and during this work, modified gears were developed and tested in a flume tank and in the field using research vessels and, to a lesser extent, commercial vessels. Next, a separate project was established to encourage acceptance of the new technologies by industry and involved workshops, newsletters and a library that lent out various by-catch reducing devices to fishers. Voluntary acceptance of the new gears is currently estimated to be 50‐80% in some ports and 0‐20% in others, and a three-phase plan for their legislation is due to occur between 1999 and 2002.In New South Wales, the main by-catch issue was the large number of undersize fish discarded by prawn trawlers as they caught prawns and other species of retained by-catch. Firstly, observer programmes on commercial vessels were used to identify and quantify size- and species-specific by-catches. Then, modifications to fishing gears that reduced the identified problematic by-catches were developed and tested on chartered commercial fishing vessels. Next, involving fishers in this work (and workshops, posters, videos, etc.) led to the voluntary acceptance of the new modifications by the majority of fishers (estimated to be 100% in some fisheries and 50‐100% in others). Finally, the new devices were made mandatory by legislation in several fisheries, with the others to follow within 12 months.In South Australia’s Gulf St. Vincent, the chief by-catch issue mainly came from the prawn-trawl industry itself and concerned the by-catch of small prawns and fish. The approach used was to begin gear-development research without any formal quantification phase. After preliminary trials by industry, only five days of formal tests of new devices were required to recommend a design that was optimal for industry’s (and management’s) requirements. Within two weeks of the completion of the field trials, 100 of the industry was using this new gear voluntarily and its legislation is planned to occur within the next few years to ensure continued compliance.The simple pattern that emerges from these examples is that the sooner industry is fully involved in all stages of the work (driving the issue, quantifying it, developing devices and implementing them), the sooner and more complete is the voluntary acceptance of by-catch reducing fishing technology, and the more painless is the implementation of the relevant legislation.

The Siriella brevicaudata species group from the West Indo-Pacific, defined and designated by Murano & Fukuoka (2008), previously contained five nominal species. In this study we describe five new species in the brevicaudata group: S. bassi sp. nov. from the Bass Strait, southern Australia, S. occulta sp. nov. from the Arabian Gulf, S. muranoi sp. nov. from the coast of Northern Territory, Australia, S. tabaniocula sp. nov. from Ningaloo Reef of Western Australia and Lodestone Reef off Queensland, and S. talbotae sp. nov. from Lizard Island, Queensland, Australia. Furthermore, Siriella hanseni W.M. Tattersall, 1922 from India and S. vincenti W.M. Tattersall, 1927 from South Australia are redescribed based on re-examination of their type material. A re-examination of specimens subsequently attributed to these two species from other geographical regions showed that these were misidentifications, partly representing three of the new species described herein. Siriella gibbosa (Ledoyer, 1970), which was previously synonymized with S. brevicaudata Paulson, 1875 by Bačescu, is revalidated and included within the brevicaudata group. Siriella lacertilis Talbot, 2009, from Lizard Island, is placed within the brevicaudata group. Diagnostic features for all the members of the group and the group itself are updated. As a result of the present study, the brevicaudata group now comprises 12 valid species.