Findings from the field: northern Bahamas


Image: The SVII camera on deck waiting to be assembled for deployment

 

The role of hurricanes in northern Bahamas

Over the last couple of days, we surveyed the northern-most cays of Bahamas – Walker’s Cay and Abaco. These very exposed sites have the highest frequency of hurricane occurrence in the Caribbean and the effects of this high level of disturbance is reflected in the transects. Many of these sites have very little structure with a low abundance and diversity of small coral colonies.

Despite this observation, it is known that hurricane activity can assist in reproduction (asexually) and dispersal of certain coral species through fragmenting of coral colonies. For example, areas with higher hurricane occurrences contribute more to the abundance and dispersal of the massive reef builder coral Montastrea annularis via fragmentation of colonies (Foster et al. 2013).

 

Thriving fish life

Apart from corals, we also noticed variations in the reef fish communities, especially after our previous expedition in the Lesser Antilles. The fishing practises of Bahamas are much more regulated than other parts of the Caribbean and again we saw the effects of regulation in our dives. Many of the fish we observed, such as the parrotfish, were in their terminal phase meaning they were in their last stage of development. As a parrotfish grows from a juvenile, they turn into females during their initial phase, then in their terminal phase, they change into males. In St. Vincent, the few parrotfish that we came across were either juveniles or in their initial phase. We also observed fish belonging to all levels of the food web, from grazers to top predators, such as sharks, snappers and groupers, while in the southern Caribbean, many of the fish were grazers and corallivores.

 

In the coming days, we move south towards Berry Cay and Nassau. It will be interesting to see how these coral and fish communities change as this area is more sheltered but also is exposed to more human impacts.

 

 

Reference: Foster NL, Baums IB, Sanchez JA, Paris CB, Chollett I, et al. (2013) Hurricane-Driven Patterns of Clonality in an Ecosystem Engineer: The Caribbean Coral Montastraea annularis. PLoS ONE 8(1): e53283. doi:10.1371/journal.pone.0053283

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