Review on hard coral recruitment (Cnidaria: Scleractinia) in Colombia

Recruitment, defined and measured as the incorporation of new individuals (i.e. coral juveniles) into a population, is a fundamental process for ecologists, evolutionists and conservationists due to its direct effect on population structure and function. Because most coral populations are self-feeding, a breakdown in recruitment would lead to local extinction. Recruitment indirectly affects both renewal and maintenance of existing and future coral communities, coral reef biodiversity (bottom-up effect) and therefore coral reef resilience. This process has been used as an indirect measure of individual reproductive success (fitness) and is the final stage of larval dispersal leading to population connectivity. As a result, recruitment has been proposed as an indicator of coral-reef health in marine protected areas, as well as a central aspect of the decision-making process concerning management and conservation. The creation of management plans to promote impact mitigation,rehabilitation and conservation of the Colombian coral reefs is a necessity that requires firstly, a review and integration of existing literature on scleractinian coral recruitment in Colombia and secondly, larger scale field studies. This motivated us to summarize and analyze all existing information on coral recruitment to determine the state of knowledge, isolate patterns, identify gaps, and suggest future lines of research.

Assessment and possible development of the fishery resources of Pedro Bank

Pedro Bank is about 1,300 square miles in extent and lies at the mouth of the Palk Strait close to the mainland, enabling smaller boats to exploit it. Trawl surveys indicated the presence of substantial demersal varieties on the Pedro Bank, but the results of the early commercial operations indicate that a 135-foot trawler may not be operated continuously on the bank without diminishing returns. Subsequent to the commercial operations extensive surveys with smaller boats and various types of gear were carried out. Of the various types of gear tried out, results from bottom long lining and hand lining operations were promising. Trials were carried out to compare these two types of gear. Though not extensive, these trials indicated that at the initial stages of exploitation of the Bank, hand lining, which is extensively practiced in Ceylon, may be better but as exploitation progresses; with more experience, it should be possible to overcome some of the present disadvantages of bottom long lining and eventually bottom long lining should produce better results. The recently introduced mechanised craft are exploiting only the fringe of the bank and it should be possible to exploit its stocks fully with slightly bigger boats with a 35-40 mile range.

Resources of the Wadge and Pedro Banks

Sri Lanka's interest in trawler fishing dates back to 1902 when a Colombo merchant attempted to operate a trawler off Sri Lanka's waters. The next attempt was made in 1907. These attempts did not proceed any further. Between 1920 and 1923 a very comprehensive survey of the littoral waters around the island was carried out. One of the principal aims of the survey was to investigate the possibility of trawler fishing in the seas around. Malpas (1926) and Pearson and Malpas (1926) reporting the results of the survey indicated that the Wadge and Pedro banks were the only areas available for commercial trawler operations and indicated that the fish resources in the two banks could be profitably exploited. Commercial exploitation of the Wadge bank commenced in 1928 and a fishery is now firmly established in the bank. The Marine Biologist and the Director of fisheries in their administration reports and Sivalingam and Medcof (1957) and the author (1965) have reported on the progress of the Wadge bank fishery. Some of the trends indicated by an analysis of the records of the commercial trawling operations are further discussed in this paper.