Has the fishery contributed to a major shift in the distribution of South African sardine?

Abstract Coetzee, J. C., van der Lingen, C. D., Hutchings, L., and Fairweather, T. P. 2008. Has the fishery contributed to a major shift in the distribution of South African sardine? – ICES Journal of Marine Science, 65: 1676–1688. A major shift in the distribution of South African sardine (Sardinops sagax) has resulted in a significant spatial mismatch in fishing effort vs. fish abundance in recent years. The sardine fishery started on the west coast during the 1940s, and processing capacity there increased rapidly. This trend together with increases in annual landings continued up to the early 1960s, but then the fishery collapsed as a consequence of overfishing. The population then recovered steadily during the 1980s and 1990s, coincident with, but perhaps not entirely attributable to, the inception of conservative management practices, to support catches similar to pre-collapse levels. Since 2001, however, most of the sardine population has been situated on South Africa’s south coast, far from processing facilities. Fishing effort has increased concomitantly on that coast, particularly during the past three years, reflecting the continued decline in the abundance of sardine on the west coast. Three hypotheses explaining the change in the distribution of sardine have been proposed: (i) intensely localized (i.e. west coast) fishing pressure depleted that part (or functionally distinct unit) of the population; (ii) the shift was environmentally induced; and (iii) successful spawning and recruit survival on the south coast contributed disproportionately more towards the bulk of recruitment, and progeny spawned there now dominate the population and exhibit natal homing. The first of these hypotheses is evaluated, and management implications of the shift discussed.

Download Full-text

Relative abundances and size compositions of champagne crabs, Hypothalassia acerba, on two coasts and in different water depths and seasons

Marine and Freshwater Research ◽

10.1071/mf04063 ◽

2004 ◽

Vol 55 (7) ◽

pp. 653 ◽

Cited By ~ 3

Author(s):

Kim D. Smith ◽

Norman G. Hall ◽

Ian C. Potter

Keyword(s):

West Coast ◽

Carapace Length ◽

South Coast ◽

The South ◽

The West ◽

Spatial Partitioning ◽

Invertebrate Predators ◽

The Mean ◽

The Difference ◽

Catch Rates

Hypothalassia acerba was sampled seasonally using traps at depths of 35, 90, 145, 200, 255, 310 and 365 m on the west and south coasts of Western Australia. Catch rates peaked at depths of 200 m on the west coast and 145 m on the south coast but at similar temperatures of 16.1–17.1°C. The west and south coast catches contained 69% and 84% males respectively. The carapace length of H. acerba declined significantly by 4 mm for each 100 m increase in depth. The maximum carapace length of males was greater than females on the west coast (135 v. 113 mm) and south coast (138 v. 120 mm). Furthermore, after adjustment to a depth of 200 m, the mean carapace lengths of males were greater than females on both the west coast (96.6 v. 94.6 mm) and south coast (101.5 v. 91.4 mm), with the difference on the south coast being significant (P < 0.001). Thus, in summary, (1) distribution was related to depth and temperature; (2) body size was inversely related to water depth; and (3) males grew larger and were caught in greater numbers than females. There was also evidence that the distribution changed slightly with season and of spatial partitioning by H. acerba and other large deep-water invertebrate predators.

Download Full-text

Bass populations and movements on the west coast of the U.K.

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400036924 ◽

1979 ◽

Vol 59 (4) ◽

pp. 889-936 ◽

Cited By ~ 16

Author(s):

Donovan Kelley

Keyword(s):

West Coast ◽

Seasonal Migration ◽

South Coast ◽

The South ◽

The West ◽

Systematic Pattern ◽

Discrete Populations

A bass tagging project on the south coast of Anglesey, 1971–5, yielded 86 recoveries from 912 taggings. In addition to expected local movements a systematic pattern of seasonal migration was identified for adults. Fish present in summer moved to south Cornwall for the winter, returning in succeeding summers for spawning. Departure was normally before mid-October. Fish present after that had summered further north (reaching Furness in warm summers). These too moved south as winter advanced, though possibly not reaching Cornwall. A few solitary fish – unfit specimens or members of weak year-classes – appeared to remain through the winter. No evidence was found of movement to, or intermingling with stocks of, the Irish coast; nor, with one exception, the mainland coast of Europe. There was also no indication of movement eastward along the south coast: suggesting discrete populations there from those on the west coast.

Download Full-text

An aerial survey for sperm whales off the coast of Western Australia 1963-1965.

Marine and Freshwater Research ◽

10.1071/mf9680031 ◽

1968 ◽

Vol 19 (1) ◽

pp. 31 ◽

Cited By ~ 7

Author(s):

JL Bannister

Keyword(s):

Continental Slope ◽

Western Australia ◽

West Coast ◽

Aerial Survey ◽

South Coast ◽

Sperm Whales ◽

The South ◽

The West ◽

Offshore Area ◽

Direction Of Movement

Objectives, methods, and results of a two-year aerial survey for sperm whales off the coast of Western Australia, 1963-65, are described. Data from commercial whaling operations have been included where appropriate. Sperm whales were found well off the west coast, but only in a narrow strip along the continental slope off the south coast. On both coasts, the main direction of movement was parallel to the coastline and towards Cape Leeuwin. Unexpectedly, whales off the west coast were heading mainly southwards throughout the year. Densities in the offshore area north of Perth were significantly higher than along the continental slope in the same region but similar to those along the continental slope from Perth to Cape Leeuwin. The situation was reversed on the south coast with whales being found, in high densities, only along the continental slope. Off the west coast, there were marked decreases in abundance in winter, with peaks in spring-early summer and autumn; no change in direction of movement could be related to the peaks. Average numbers calculated as present in the survey area at one time were: west coast, c. 1000 whales; south coast, c. 200 whales. South coast data indicate the passage of about 40 whales in one 24 hr period, very similar to results from whaling company aerial spotter data off Albany. The hypothesis of two separate populations of sperm whales off Western Australia is discussed and thought to be unlikely. A small amount of data on baleen whale sightings is recorded.

Download Full-text

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.

Download Full-text

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.

Download Full-text

Genomic divergence and differential gene expression between crustacean ecotypes across a marine thermal gradient

10.1101/2020.09.04.282517 ◽

2020 ◽

Author(s):

Arsalan Emami-Khoyi ◽

Ingrid S. Knapp ◽

Daniela M. Monsanto ◽

Bettine Jansen van Vuuren ◽

Robert J. Toonen ◽

...

Keyword(s):

Gene Expression ◽

West Coast ◽

Environmental Gradients ◽

Expression Profiles ◽

Molecular Dating ◽

South Coast ◽

Decapod Crustaceans ◽

The West ◽

Widespread Species ◽

Genomic Divergence

AbstractEnvironmental gradients between marine biogeographical provinces separate distinct faunal communities; in the absence of absolute dispersal barriers numerous species nonetheless occur on either side of such boundaries. While the regional populations of such widespread species tend to be morphologically indistinguishable from each other, genetic evidence suggests that they represent unique ecotypes, and likely even cryptic species, that may be uniquely adapted to their local environment. Here, we explored genomic divergence in four sympatric southern African decapod crustaceans whose ranges span the boundary between the cool-temperate west coast (south-eastern Atlantic) and the warm-temperate south coast (south-western Indian Ocean) near the southern tip of the African continent. Using genome-wide data, we found that all four species comprise distinct west- and south coast ecotypes, with molecular dating suggesting divergence during the Pleistocene. Using transcriptomic data from one of the decapod crustaceans, we further found a clear difference in gene expression profiles between the west- and south coast ecotypes. This was particularly clear in the individual from the south coast, which experienced a ‘transcriptomic shock’ at low temperatures that are more typical of the west coast and may explain their absence from that coastline. Our results shed new light on the processes involved in driving genomic divergence and incipient speciation.

Download Full-text

Comparison of Three Production Scenarios for Buxus microphylla var. japonica ‘Green Beauty’ Marketed in a No. 3 Container on the West Coast Using Life Cycle Assessment

HortScience ◽

10.21273/hortsci11596-16 ◽

2017 ◽

Vol 52 (3) ◽

pp. 357-365 ◽

Cited By ~ 2

Author(s):

Dewayne L. Ingram ◽

Charles R. Hall ◽

Joshua Knight

Keyword(s):

Life Cycle Assessment ◽

Life Cycle ◽

Best Management Practices ◽

West Coast ◽

Management Practices ◽

The United States ◽

The West ◽

Best Management ◽

Buxus Microphylla ◽

Carbon Dioxide Equivalents

Three scenarios for production of Buxus microphylla var. japonica [(Mull. Arg.) Rehder & E.H. Wilson] ‘Green Beauty’ marketed in a no. 3 container on the west coast of the United States were modeled based on grower interviews and best management practices. Life cycle inventories (LCIs) of input products, equipment use, and labor were developed from the protocols for those scenarios and a life cycle assessment (LCA) was conducted to determine impact of individual components on the greenhouse gas emissions (GHGs) and the subsequent carbon footprint (CF) of the product at the nursery gate and in the landscape. CF is expressed in global warming potential (GWP) for a 100-year period in units of kilograms of carbon dioxide equivalents (kg CO2e). The GWP of the plant from Scenario A (propagation to no. 1 to 3 container) was 2.198 kg CO2e with variable costs of $4.043. Scenario B (propagation to field to no. 3 container) would result in a GWP of 1.717 kg CO2e with variable costs of $2.880 and take a year longer in production than the other two models. The GWP of Scenario C (propagation to no. 1 to no. 2 to no. 3 containers) would be 3.364 kg CO2e with variable costs of $5.733. Containers, transplants/transplanting, irrigation, and fertilization input products and associated activities accounted for the greatest portion of GHG and variable costs in each scenario. Pruning, assembling/load trucks, pesticides, and chlorination were other important components to variable costs of each scenario but had little impact on GWP. Otherwise, the major contributors to GWP are also major contributors to cost.

Download Full-text