Mitigation of incidental mortality of Australian sea lions in the west coast rock lobster fishery

The Australian sea-lion, Neophoca cinerea, has a 17-18-month breeding cycle on islands off the west coast of Western Australia. Buller, North Fisherman and Beagle Is are the main pupping sites, with several very small colonies (n> 3) at the Abrolhos Is. The 4-5-month pupping seasons are synchronised at North Fisherman and Beagle Is, but the sea-lions from Buller I. breed one month later and those from the Abrolhos Is two months earlier. Pup production and pup mortality were highly variable between seasons over which observations were recorded: 129 pups were born at the main breeding sites in early 1988, the mortality in the first five months was 7.1%, whereas 181 pups were born in late 1989 of which 24.3% died. Pups remain in the vicinity of their natal islands for the first 4-5 months of life before leaving, perhaps on foraging trips, with their mothers. Most return to their natal island, although others haulout on islands up to 27 km away. Some male N. cinerea congregate in bachelor colonies on islands adjacent to the Perth metropolitan region during the non-breeding season and migrate up to 280 km north each breeding season. The status of the isolated, west-coast N. cinerea population is unknown. The current high level of human pressure on sea-lion terrestrial habitats and their food resources indicate a need for further monitoring of this species.

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Jasus lalandii 'walkouts' or mass strandings in South Africa during the 1990s: an overview

Marine and Freshwater Research ◽

10.1071/mf01100 ◽

2001 ◽

Vol 52 (8) ◽

pp. 1085 ◽

Cited By ~ 47

Author(s):

Andrew C. Cockcroft

Keyword(s):

South Africa ◽

West Coast ◽

The Other ◽

Fishing Industry ◽

Low Oxygen ◽

Rock Lobster ◽

The West ◽

Hypoxic Conditions ◽

Oxygen Conditions ◽

Mass Mortalities

Faunal mass mortalities are a sporadic, but not uncommon, feature of the West and South coasts of South Africa. Five mass mortalities of West Coast rock lobsterJasus lalandii, including three of the most severe ever recorded in South Africa, occurred in the 1990s and resulted in the stranding of about 2263 tonnes of lobster. The bulk (97%) of the loss occurred in the last three years of the decade. The five events occurred within an 80 km stretch of coastline that straddled two fishing zones and resulted from hypoxic conditions associated with highbiomass dinoflagellate blooms. In each case, the quantity of lobsters stranded was directly related to the extent or duration of low-oxygen conditions. Small females constituted the bulk of the lobster stranded in most events. The lobster fisheries in the affected fishing zones suffered severe impacts. Recovery in one zone appears to be extremely slow, whereas the other zone is more resilient. Not only would a continuation of the trend of increasing frequency and severity of lobster strandings devastate the rock-lobster fishing industry and the employment prospects of small fishing communities, but it could also seriously affect the ecology of the region.

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Mitochondrial DNA variation of the west-coast rock lobster, Jasus lalandii: marked genetic diversity differences among sampling sites

Marine and Freshwater Research ◽

10.1071/mf07138 ◽

2007 ◽

Vol 58 (12) ◽

pp. 1130 ◽

Cited By ~ 21

Author(s):

Conrad A. Matthee ◽

Andrew C. Cockcroft ◽

Keshni Gopal ◽

Sophie von der Heyden

Keyword(s):

Genetic Diversity ◽

West Coast ◽

Haplotype Network ◽

Phylogeographic Structure ◽

Rrna Gene ◽

Rock Lobster ◽

The West ◽

Mt Dna ◽

Dna Variation ◽

Intensive Exploitation

Jasus lalandii (Milne-Edwards 1837), the west-coast rock lobster, occurs in the shallow, cool–temperate waters along the south and west coasts of southern Africa. This species has a long history of intensive exploitation, which has had a significant impact on population numbers in the past. To enhance our current understanding of lobster population structuring, genetic data from the mitochondrial (mt) DNA 16S rRNA gene was generated for 235 adult individuals collected at eight sampling sites. Most individuals (59.6%) share a common haplotype and 35 unique haplotypes were dispersed throughout the range. In total, 97.2% of the variation was found among individuals within sampling sites and 2.8% was among sites. Pairwise ΦST analyses revealed shallow, yet significant structure between Hout Bay individuals and some other sampling sites. The J. lalandii haplotype network indicates a starlike structure with no geographic signal; however, genetic diversity sharply decreases towards the edges of the species distribution. The general lack of phylogeographic structure among J. lalandii populations probably results from the absence of strong barriers to larval dispersal. Based on our mtDNA data there is no justification for the recognition of separate fishing stocks, but the high genetic diversities of populations at Hout Bay and Cape Hangklip, the latter currently outside of marine protected areas, makes these populations critical to conservation efforts.

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Westland petrel (Procellaria westlandica) foraging behaviour: Patterns and drivers of individual variation

10.26686/wgtn.17204045.v1 ◽

2021 ◽

Author(s):

◽

Douglas Rands

Keyword(s):

Habitat Selection ◽

West Coast ◽

Foraging Behaviour ◽

Sea Surface ◽

Foraging Strategies ◽

Sea Surface Temperatures ◽

The West ◽

Surface Temperatures ◽

Foraging Site ◽

Incidental Mortality

Foraging behaviour can have a major influence on the survival and reproduction of individuals which can ultimately impact the viability of a population. Foraging is particularly challenging for procellariiformes (tube nosed seabirds) who feed on patchily distributed prey in the highly dynamic marine environment. During the breeding season procellariiformes must also increase their foraging effort to raise their chick whilst having a reduced foraging range. As a result, procellariiformes have adopted various foraging strategies, such as dual foraging and sexual foraging dimorphism, to cope with this energy demanding lifestyle. Westland petrels (Procellaria westlandica) are an endangered winter breeding procellariform endemic to the West Coast of New Zealand’s South Island. Unlike other procellariiformes, previous studies have found little evidence of Westland petrels using sexually dimorphic or dual foraging strategies. Furthermore, Westland petrels also display a high level of individual variation in foraging behaviour. To understand why there is so much variation and what factors are driving it, I first examined variation at the population, individual and within individual level to describe and categorise different foraging strategies. I then investigated how factors such as year, sex and foraging site influenced variation. Finally, I examined how oceanic variables influenced habitat selection and foraging characteristics to understand how the environment drives variation in foraging behaviour. Considerable variation was found at all levels. Most of the variation was explained by year with individuals taking shorter foraging trips in 2011 and longer trips in 2015. Females foraged further than males suggesting that there is some degree of sexual foraging segregation occurring in Westland petrels. I also found that the highest variation in foraging behaviour was exhibited by individuals within their core foraging site on the West Coast. Sea surface temperatures were highest at the West Coast foraging site and individuals within this site showed differences in habitat selection among years. Habitat selection at the West Coast site also differed between sexes suggesting that males are outcompeting females for prime foraging spots. Overall, my results indicate that foraging conditions on the West Coast are highly variable likely due to rising sea surface temperatures, marine heatwaves, and the effects of the El Nino-Southern Oscillation. As a result, it is likely that prey availability on the West Coast is unpredictable causing high variation in foraging behaviour and sexual foraging segregation. With climate change, foraging conditions on the West Coast are predicted to get more unpredictable as sea surface temperatures continue to rise and extreme weather events become more frequent. These factors will make foraging increasingly difficult for Westland petrels and could see them rely more on fishery discards as a source of food, increasing their risk of incidental mortality. Conservation management should focus on protecting the petrels core foraging area around the Hokitika canyon to help limit the effects of climate change. Fishery management should also focus on limiting or prohibiting offal discards to prevent the incidental mortality of Westland petrels.

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Westland petrel (Procellaria westlandica) foraging behaviour: Patterns and drivers of individual variation

10.26686/wgtn.17204045 ◽

2021 ◽

Author(s):

◽

Douglas Rands

Keyword(s):

Habitat Selection ◽

West Coast ◽

Foraging Behaviour ◽

Sea Surface ◽

Foraging Strategies ◽

Sea Surface Temperatures ◽

The West ◽

Surface Temperatures ◽

Foraging Site ◽

Incidental Mortality

Foraging behaviour can have a major influence on the survival and reproduction of individuals which can ultimately impact the viability of a population. Foraging is particularly challenging for procellariiformes (tube nosed seabirds) who feed on patchily distributed prey in the highly dynamic marine environment. During the breeding season procellariiformes must also increase their foraging effort to raise their chick whilst having a reduced foraging range. As a result, procellariiformes have adopted various foraging strategies, such as dual foraging and sexual foraging dimorphism, to cope with this energy demanding lifestyle. Westland petrels (Procellaria westlandica) are an endangered winter breeding procellariform endemic to the West Coast of New Zealand’s South Island. Unlike other procellariiformes, previous studies have found little evidence of Westland petrels using sexually dimorphic or dual foraging strategies. Furthermore, Westland petrels also display a high level of individual variation in foraging behaviour. To understand why there is so much variation and what factors are driving it, I first examined variation at the population, individual and within individual level to describe and categorise different foraging strategies. I then investigated how factors such as year, sex and foraging site influenced variation. Finally, I examined how oceanic variables influenced habitat selection and foraging characteristics to understand how the environment drives variation in foraging behaviour. Considerable variation was found at all levels. Most of the variation was explained by year with individuals taking shorter foraging trips in 2011 and longer trips in 2015. Females foraged further than males suggesting that there is some degree of sexual foraging segregation occurring in Westland petrels. I also found that the highest variation in foraging behaviour was exhibited by individuals within their core foraging site on the West Coast. Sea surface temperatures were highest at the West Coast foraging site and individuals within this site showed differences in habitat selection among years. Habitat selection at the West Coast site also differed between sexes suggesting that males are outcompeting females for prime foraging spots. Overall, my results indicate that foraging conditions on the West Coast are highly variable likely due to rising sea surface temperatures, marine heatwaves, and the effects of the El Nino-Southern Oscillation. As a result, it is likely that prey availability on the West Coast is unpredictable causing high variation in foraging behaviour and sexual foraging segregation. With climate change, foraging conditions on the West Coast are predicted to get more unpredictable as sea surface temperatures continue to rise and extreme weather events become more frequent. These factors will make foraging increasingly difficult for Westland petrels and could see them rely more on fishery discards as a source of food, increasing their risk of incidental mortality. Conservation management should focus on protecting the petrels core foraging area around the Hokitika canyon to help limit the effects of climate change. Fishery management should also focus on limiting or prohibiting offal discards to prevent the incidental mortality of Westland petrels.

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Improving the catch efficiency of the West Coast rock lobster, Jasus lalandii

Marine and Freshwater Research ◽

10.1071/mf99063 ◽

2000 ◽

Vol 51 (6) ◽

pp. 613 ◽

Cited By ~ 4

Author(s):

D. Loewenthal ◽

S. Mayfield ◽

G. M. Branch

Keyword(s):

Weight Loss ◽

South African ◽

West Coast ◽

Capture Rate ◽

Catch Rate ◽

Rock Lobster ◽

The South ◽

The West ◽

The Relationship

The South African commercial rock-lobster industry employs an average soak time of 22 h for traps. Experiments were undertaken to test (1) the rate of bait loss with soak time and the effect that protection of the bait has on bait loss, (2) the relationship between catch rate (numbers per trap) and soak time for traps with either protected or unprotected bait, and (3) the effect of two bait types (whole maasbanker and hake heads) on the catch of rock lobsters. There were substantial losses of unprotected bait within 6 h; substantially less weight loss was observed from protected bait even after a 48-h soak time. The numbers of rock lobsters caught in traps with unprotected bait were low relative to the capture rate with protected bait. The highest capture rate occurred after 6 h for unprotected bait and 6–12 h for protected bait. There was no significant effect of bait type (maasbanker v. hake heads) on the number or size of rock lobsters. To optimize catch efficiency, the commercial industry should use protected bait and soak times as short as 6–12 h.

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The South African Fisheries: A Preliminary Survey of Historical Sources

The Exploited Seas ◽

10.5949/liverpool/9780973007312.003.0008 ◽

2001 ◽

pp. 167-180

Author(s):

Lance van Sittert

Keyword(s):

South African ◽

West Coast ◽

Marine Resources ◽

Historical Records ◽

Preliminary Survey ◽

Rock Lobster ◽

The South ◽

Historical Sources ◽

The West

Lance van Sittert explores the historical records concerning the exploitation of marine resources along the West Coast of Africa, using them to provide evidence of the commerical importance of the West Coast over the East or South. The date demonstrates a boom-bust cycle along the West Coast, pertaining to whales, snoek, guano, rock lobster, hake, and pilchard.

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World wide fund for nature South Africa (WWF) and the case of the West Coast rock lobster

Emerald Emerging Markets Case Studies ◽

10.1108/eemcs-03-2021-0067 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1-22

Author(s):

Taryn Miller

Keyword(s):

West Coast ◽

World Wide ◽

Stakeholder Management ◽

Responsible Leadership ◽

Rock Lobster ◽

The West ◽

Total Allowable Catch ◽

Content Type ◽

Legal Provisions ◽

The Government

Subject area The following subjects are addressed through the case: Integrated thinking; professional skills; ethics and values; sustainability; and responsible leadership. Study level/applicability This teaching case is aimed at Postgraduate accounting honours or masters students or MBA students. Case overview The case begins on 16 May 2018, with Jason Roberts, Head of Environmental Programmes at World wide fund for nature (WWF), reflecting over bad news. The Department of Agriculture, Forestry and Fisheries (“DAFF”, also referred to as “government”), have just approved the 2017/2018 Total Allowable Catch (“TAC”) for the West Coast (WC) rock lobster at 1,924 tons, almost three times the amount recommended by the scientific community. The events describe a history of tension between the primary objectives of the WWF and the government; difficulties in stakeholder management, and the potential consequences for the survival of the WC rock lobster and those who depend on it for their livelihood. The different perspectives held by different stakeholders; the relevance of the scientific evidence; the legal provisions in place and the process applicable to making the TAC decision; all highlight the complex environment in which decisions were made; to which the WWF is wondering how to respond. Expected learning outcomes The case’s primary learning objective is to highlight the variety of considerations involved in complex decision-making, also known as “integrated thinking”. Students will be required to critically analyse and evaluate the information in the case, as well as the exhibits; to comment on the appropriateness of various decisions and recommendations; evaluate the ethical/moral responsibilities of WWF; understand different perspectives and the reasons for these perspectives; identify actions and statements that reflect responsible leadership, as well as those that reflect the contrary; and apply learnings from this case to personally reflect on one’s role as a responsible business leader. Supplementary materials Teaching Notes are available for educators only. Subject code CSS 1: Accounting and Finance.

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Ocean circulation, Stokes drift, and connectivity of western rock lobster (Panulirus cygnus) population

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f2011-065 ◽

2011 ◽

Vol 68 (7) ◽

pp. 1182-1196 ◽

Cited By ~ 34

Author(s):

Ming Feng ◽

Nick Caputi ◽

James Penn ◽

Dirk Slawinski ◽

Simon de Lestang ◽

...

Keyword(s):

Ocean Circulation ◽

West Coast ◽

Early Stage ◽

Austral Summer ◽

Early Summer ◽

Stokes Drift ◽

Rock Lobster ◽

The West ◽

Larval Phase ◽

Panulirus Cygnus

An individual-based model, incorporating outputs of a data-assimilating hydrodynamic model, was developed to investigate the role of ocean circulation in the recruitment processes of western rock lobster ( Panulirus cygnus ) during its 9- to 11-month larval phase off the west coast of Australia. During austral summer, strong northward alongshore winds aid the offshore movement of early-stage model larvae from midshelf hatching sites into open ocean; during austral winter, eastward flows that feed the enhanced Leeuwin Current facilitate onshore movement of late-stage larvae towards nearshore habitats. Stokes drift induced by swells from the Southern Ocean is critical to retain larvae off the west coast. Diurnal migration and temperature-dependent growth are also important. Model larvae hatched in late spring – early summer grow faster because of longer exposure to warm summer temperature, which allows them to be transported towards the coast by the strong onshore flows in winter and reduces their natural mortality. Preliminary source–sink relationship indicates that the population was well mixed off the coast, with higher likelihood of settlement success from hatching sites in the north, mostly due to higher surface temperature. Weighted with the breeding stock distribution, the area between 27.5°S and 29.5°S, including the Abrolhos Islands, is the most important hatching area to the success of settlement.

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