Squid, scuba diving and fish dissections

Christina Hunt

Squid, scuba diving and fish dissections. Those three things sum up my undergraduate fieldwork in Honduras, Central America. I was based on the tropical island paradise of Utila, where during the summer months a small dive centre transitions into a hub of marine research activity. The site is run by a team of scientists and PhD students, assisted by plenty of enthusiastic volunteers and undergraduate students. Research conducted on Utila contributes to our knowledge of Caribbean reefs, and this is used to guide conservation management, both within Honduras and across the Caribbean.

The position of Utila, Honduras within Central America (Google, 2017)
A diver prepares to jump into the water (By Christina Hunt)

Here is a brief overview of life at the ‘Coral View Research Lab’:
At 7:30 every morning the boats set off ready for the first research dive of the day. As the boats make their way to the dive sites, the objectives of the dive are discussed and any special equipment is prepared. On arrival at the dive site the divers kit up, conduct their buddy checks and then enter the water. For divers on the smallest boat, this involves the characteristic backward roll entry into the water.

One of the boats will be carrying ‘Team lionfish’. Lionfish (Pterois volitans and P. miles) are invasive species that are taking over Caribbean coral reefs because they have a high reproductive rate and are very efficient predators1. Because lionfish do not belong in the Caribbean, they are the focus of research and culling efforts. When a lionfish is sighted by a member of the team, its depth and behaviour are recorded. An experienced diver then humanely kills the lionfish. Back on dry land the lionfish are taken to the lab and dissected, providing crucial information such as size, gender and diet. This data is used by scientists to inform lionfish management.

Reef scene (By Christina Hunt)

Another dive boat will be carrying a stereo-video system. This is a special camera set-up using two video cameras which film partially overlapping images. Divers swim a set distance along the reef, filming as they swim, and the resulting footage is then analysed on computers back at the dive centre. Because the cameras are a known distance apart, if a fish is recorded in both images then computer software can calculate the length of the fish. The biomass of fish can then be calculated using known length-weight ratios. This data can be used to compare fish communities between sites, but also to assess whether the communities observed differ when filmed by normal scuba divers (whose kit produces bubbles) compared to rebreather divers (whose kit does not produce bubbles).

The third boat will be carrying the sea urchin team. Sea urchins are important for grazing algae and preventing it from overgrowing the coral. Sea urchin abundance plummeted in 1983 due to disease and although there has been some recovery, populations are only a fraction of their former size2. The sea urchin team survey the reefs to document sea urchin abundance and investigate possible barriers to full population recovery.

Neptune’s beach, Utila (By Christina Hunt)

One day a week is ‘off-gassing’ day. This is essential because over time nitrogen builds up in a diver’s tissues and excess nitrogen can lead to decompression illness. Many people take the opportunity to go snorkelling on their day off and during my time on Utila I was rewarded with sightings of squid, stingrays and three species of eel! A group of squid is officially known as a shoal, however, many people prefer the term a ‘squad of squid’! Several times I witnessed as many as 20 squid swimming along side by side in a perfect line!

So there you have it- a brief overview of marine biology field research in the Caribbean. I enjoyed my fieldwork so much that I joined the Environmental Research Doctoral Training Partnership at Oxford University so that I can study lionfish for my PhD! My undergraduate research focused on the detrimental effects of lionfish, but my PhD is going to focus on how we can improve lionfish management. Hopefully my PhD will improve the efficiency and success of lionfish control, and this will allow ecologically and economically important native species to recover.

All of my fieldwork (undergraduate and PhD) is made possible by the organisation ‘Operation Wallacea’. If you are interested in conducting fieldwork for an undergraduate, Masters or PhD degree, or you just want to help as a volunteer, then check out: www.opwall.com. Operation Wallacea has field sites all around the world, and they conduct both marine and terrestrial research.


1Albins, M.A and Hixon, M.A. (2013) Worst case scenario: potential long-term effects of invasive predatory lionfish (Pterois volitans) on Atlantic and Caribbean coral-reef communities. Environmental Biology of Fishes. 96 (10): 1151-1157.
2Bodmer, M.D.V et al. (2015) Using an isolated population boom to explore barriers to recovery in the keystone Caribbean coral reef herbivore Diadema antillarum. Coral Reefs. 34 (4): 1011-1021.

“I am a first year DTP student studying the ecology and behaviour of invasive lionfish in Honduras. I am particularly interested in aggregation behaviour, and how this can be exploited to improve lionfish control.”


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