Variation in Dispersal of Galjoen (Coracinus capensis) (Teleostei: Coracinidae) from a Marine Reserve

1994 ◽  
Vol 51 (6) ◽  
pp. 1247-1257 ◽  
Author(s):  
Colin G. Attwood ◽  
Bruce A. Bennett
Keyword(s):  
South Africa ◽  
Spatial Variability ◽  
Surf Zone ◽  
Marine Reserve ◽  
Adult Fish ◽  
Large Uncertainty ◽  
Dispersal Behaviour ◽  
Movement Rates ◽  
Random Dispersal

The dispersal of the surf-zone teleost galjoen (Coracinus capensis) from the De Hoop Marine Reserve, South Africa, was investigated. Over a period of 5.5 yr, 11 022 galjoen were tagged in the centre of the reserve. Most of the 1008 recoveries were at the site of release, while the remainder covered a distance of up to 1040 km. There was no difference with respect to age, sex, or season between those that dispersed and those that did not. Six models were developed to test the hypotheses that (1) galjoen are polymorphic with respect to dispersal behaviour, (2) nonreporting of tags masks a random dispersal process, and (3) the recovery distribution is the result of unequal movement rates in different areas. It is inferred from the likelihoods of the various models that the tagged population was polymorphic, with fish displaying either resident or nomadic behaviour. This conclusion is unaffected by a large uncertainty in the extent of nonreporting of recoveries, or by spatial variability of movement rates. The estimate of emigration from the reserve implies that the unharvested reserve population is restocking adjacent exploited areas with adult fish.

scholarly journals Preliminary assessment of surf-zone and estuarine line-fish species of the Dwesa-Cwebe Marine Protected Area, Eastern Cape, South Africa

Koedoe ◽  
2012 ◽  
Vol 54 (1) ◽  
Author(s):  
Jan A. Venter ◽  
Bruce Q. Mann
Keyword(s):  
South Africa ◽  
Law Enforcement ◽  
Fish Species ◽  
Protected Area ◽  
Surf Zone ◽  
Marine Protected Area ◽  
Fish Populations ◽  
Estuarine Fish ◽  
Catch Per Unit Effort ◽  
Preliminary Assessment

A preliminary assessment of surf-zone and estuarine line fish was carried out in the DwesaCwebe Marine Protected Area (MPA), on the Wild Coast, South Africa. The purpose was to provide baseline data on inshore line-fish stocks in the MPA. A total of 28 species was recorded, of which 53% have a conservation status reflecting some concern and 43% are endemic to southern Africa. This highlights the value of the MPA for protection of important line-fish species. Within the MPA, localised differences were detected in species diversity, size frequency and catch per unit effort between unexploited and illegally exploited areas. These differences were more prominent in slow growing, long-lived species. It thus appears that illegal exploitation is negatively affecting fish populations within the MPA, which counteract and potentially could eliminate the benefits of fish protection typically associated with no-take MPAs. These results highlight the need for improved law enforcement and better communication with neighbouring communities to increase awareness. It is further recommended that the current no-take status of the MPA should be maintained. In addition, baseline fisheries information was collected on certain fish species that could be used to inform future conservation management of the MPA.Conservation implications: The Dwesa-Cwebe Marine Protected Area is unique and important for the conservation of key surf zone and estuarine fish species. However there is a significant risk to the fish populations due to illegal exploitation. Key interventions should include enhanced law enforcement but, more important, the creation of alternative livelihoods and long term sustainable benefits to local communities.

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