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Fisheries topics
IH320 Size, diversity and abundance of groupers on coral reefs in the Wakatobi Marine National Park, Indonesia (Weeks 2 - 8; need to have completed IH007 and be dive trained) How has the reopening of the Hoga No Take Area (NTA) to fishing three years ago affected grouper abundance, size and diversity? In 2007, a study was published detailing the effects of the small NTA off Hoga Island indicating that it had positive effect on grouper size, diversity and abundance. Grouper are a key food species of the region and are highly desirable. The NTA has now been reopened (for 5 years) and the primary aim of this research is to quantify the effects of the reopening of the NTA on grouper populations by examining the abundance and size of key grouper species within the old NTA as compared to outside (horizontal comparisons). Data are available from 2007 and could be compared to that obtained during 2012 both within and outside the NTA to determine if the rates of change in the NTA are greater or smaller than sites that have always been fished. This research is only suitable for scuba divers and will include habitat quality surveys as well as fish data collection.
IH321 Changes in the Kaledupa reef fishery in Indonesia over the period 2007 to 2012 (Weeks 2 - 8; need to have completed IH007) Monitoring of fish catch data from 2007 onwards has shown that overfishing by artisanal fishers from Kaledupa has severely depleted fish stocks around the island. This topic is designed to repeat the detailed surveys from 2007 to 2010 of fish landings at 9 villages over an 8 week period. Fishers returning their catches to shore will be intercepted to gather data on the catch techniques used and the effort. The total catch will be photographed spread out on a tarpaulin with a standard rule in the picture, so that the species and lengths of each (and hence weight) can be measured from image analysis. Using the photo technique ensures that fishers are only momentarily delayed on their way to market. These data can then be used to compare catch per unit effort and the percentage of juveniles being caught by each of the main techniques with previous years. The effect of the recent fishery byelaws that are being introduced around the various communities to promote fishery recovery can then be assessed. Within this overall topic, a series of separate dissertations could be developed concentrating on different gear types (e.g. fish fences, gill nets, bubu traps, line fishing), or focusing on particular taxa of reef fish (e.g. herbivores or predatory species).
IH322 The survival rate of newly settled fish larvae on reefs of varying predator density and habitat quality, Indonesia (Weeks 2 - 8; need to have completed IH007 and be dive trained) Larvae of nearly all reef fish species are dispersed into the open ocean whilst still in the egg or shortly after hatching. This unusual but nearly ubiquitous strategy has most likely evolved to avoid predation and thus maximise survival potential. When larvae return to the reef after their period in the open ocean, they encounter a “wall of mouths” and very few make it to settlement, with mortality rates estimated at over 99%. In the Wakatobi region, heavy fishing pressure may act to reduce the number of large predatory fish and increase the survival rate of the newly recruited larvae, the combined effect of which may significantly impact the community structure. One project could quantify the survival rate of newly settled fish in relation to predator density and species composition on different reefs through underwater visual censuses or by creating experimental patch reefs in areas under different fishing pressure. In conjunction with information on reef quality and structure, this study would help understand the change in community composition in heavily fished areas and aid in the implementation of Marine Protected Areas. This research requires in water activity and is suitable for those interested in diving or snorkelling based research.
IH323 The behaviour of cleaner fish and mimics - Does this affect the resilience of reef fish communities? (Weeks 2 - 8; need to have completed IH007 and be dive trained if incorporating a diving element) The Wakatobi Marine National Park is unusual in that three speices of cleaner wrasse are present on its reefs. The Bluestreak Cleaner Wrasse (Labroides dimidiatus) has been well studies but few studies have focused on the behaviour and ecology of the other two cleaner wrasse species: the Blackspot (Labroides pectoralis) and Bicolour (Labroides bicolor). One project could examine a combination of two or all three species of cleaner wrasse in order to determine differences in distribution, territory size, densities, overlap between species and what effects they have on each other through either direct (aggressive or co-operative) on indirect (competitive) interactions. Research within this area could also examine differences in cleaning behaviour between all 3 species, using focal observations on cleaning stations. This could include: variation in time spent cleaning, visitors to cleaning station and behavioural differences in socialisation and seeking of clients. Two factors have been proposed as the main motivation for clients to seek cleaners. The first is related to relieving the irritation ectoparasites cause to their hosts' skin. The alternative is that clients are seeking cleaners to obtain tactile stimulation. Tactile stimulation is defined as the cleaner fish hovering above the client and touching its dorsal fin area with its pectoral fin and, in particular, pelvic fins. Cleaners have been shown to provide more tactile stimulation to predatory clients compared to non-predatory clients and that tactile stimulation can be used to manipulate the time spent by clients at a cleaning station. One project could determine if cleaners provide more tactile stimulation to 'floaters' (fish that can choose to visit alternative cleaning stations of their larger territory size or lack of territorial behaviour) compared to 'residents' (i.e. fish with small territories). Research within this topic could also examine which species and sizes of individuals are most commonly cleaned, whether tactile stimulation increases cleaning duration and also if the other two species of cleaner use tactile stimulation. There is also a fang blenny species that mimics the cleaner fish but instead of cleaning, the fish takes the opportunity to bite chunks out of the fish waiting to be cleaned. The presence of this 'cheat' in the system opens all sorts of possibilities for modeling use game theory.
HC324 Queen Conch distribution and ecology around the Cayos Cochinos, Honduras(Weeks 5 - 10; need to have completed the reef ecology course HU007 or HC008 and be dive trained)The Queen Conch plays a highly important role in the ecology and economics of the reefs around the Caribbean and the Cayos Cochinos Islands. However, conch are a valuable food product and over-fishing in previous years has severely reduced the populations on the reefs and seagrass beds of the Cayos. The MPA around the islands is designed to prevent the extraction of conch by fishermen and allow the conch population to recover. This project will continue an ongoing monitoring and tagging program studying the population, growth and movement of Queen Conch within the MPA from a series of sites that have been surveyed in previous years. Surveys would use the transect surveys to record conch populations, including re-measuring tagged conch from previous years and tagging and measuring new individuals. Data will assess the size class distribution of the species and quantify their recovery within the area. Projects can include more detailed behavioural and movement research by recording positional data of individual conch on a daily basis in a defined study area or look at habitat preference by doing surveys of the locations in which conch are common. The project could also identify potential levels of sustainable fishing for this species once the population has recovered and how it could be regulated to benefit the local fishing communities.
PP325 A comparison of fish diversity in different habitats in the Peruvian Amazon (Weeks 2 - 8; need to have completed PP001) This topic could be developed in a number of ways. For example, one project could compare fish communities in a range of habitats in the reserve, including shoreline edge of oxbow lakes with connections to the main river still remaining, open water areas of oxbow lakes still connected to the main river, edge and open water areas of oxbow lakes not linked to the main river and the main river edge. Sampling could be done using 30m X 3m gill nets with 3 inch mesh and fished for as close to 1 hour as possible. Large catches of fish can result in piranhas attacking the gill netted fish and on these occasions the net has to be retrieved before the full hour has passed. When this happens, the nets need to be repositioned until constant fishing effort has been achieved. Replicate sites could be chosen to represent these habitat types and multiple one-hour catches made at each of these sites. Projects on fish diversity usually have a large amount of data.
MN326 Stream fish diversity and microhabitat utilization in Mahamavo, Madagascar (Weeks 1 – 6) Very little is known about the species and distribution of stream fish in the vicinity of Mahamavo in Madagascar. Many species of fish in Madagascar are highly threatened or endangered because of deforestation, diversion for irrigation and introduced species. There are least three shallow water braided streams accessible from the Mariarano base camp. Surveys will be accomplished by seining these shallow water sand bottomed streams. The species of assemblages of each stream will be determined and the microhabitat of each species discovered will be determined as well. An effort will also be made to interview local fishermen to determine the kinds and numbers of fish found in rivers too deep for seining. This should add substantially to the total vertebrate species list for this region.
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