Intertidal size-frequency distributions and densities for Haliotis midae and Turbo sarmaticus were examined at 10 sites experiencing varying pressure of human exploitation along the southern section of the Eastern Cape coast, South Africa. Target species' densities and maximum sizes were related both to the numbers of collectors on the shore and to indirect indicators of exploitation such as number of households in the vicinity and distance to the nearest beach access point. For both species, there was variation in density (P < 0.05) and size (P < 0.05) among sites, with densities ranging between 0.03-2.23 m^(-2) and 0.07-4.93 m^(-2) for H. midae and T. sarmaticus, respectively. Maximum sizes ranged between 49.4-153.5 mm (H. midae) and 28.3-104.4 mm (T. sarmaticus) shell length. Population parameters such as mean maximum size and total density were significantly negatively related to exploitation indicators for both species. In addition, densities of sexually mature and legal-size individuals of T. sarmaticus were significantly negatively related to the number of households. However, only for H. midae were densities of subadults significantly negatively related to the number of collectors, suggesting that reproduction of abalone may be suppressed at the most exploited sites. Exploitation of T. sarmaticus tends to be localized near population centres, whereas H. midae is collected over a larger range of sites. Overall, T. sarmaticus is less affected by exploitation than H. midae.
| Identifer | oai:union.ndltd.org:Rhodes/oai:eprints.ru.ac.za:359 |
| Date | 04 1900 |
| Creators | Proudfoot, L., Kaehler, S., McGarry, D.K., Uppink, P.A., Aereboe, M., Morris, K.M. |
| Source Sets | Rhodes University SA |
| Detected Language | English |
| Type | Article, PeerReviewed |
| Format | application/pdf |
| Relation | http://eprints.ru.ac.za/359/ |
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