By: Kendra Karr & Valerie Miller
Intro by Dan Whittle: With generous support from the Waitt Foundation, Environmental Defense Fund (EDF) has launched a new initiative to support collaborative field research with scientists from the University of Havana's Center for Marine Research. This initiative is enabling teams of Cuban, U.S. and Mexican scientists to carry out a series of scientific expeditions to conduct important new research on Cuba's remarkable—but understudied—marine and coastal ecosystems. This effort will also support year-round port sampling of shark fishery landings at Cuban ports, contributing to EDF’s overarching tri-national shark conservation efforts throughout the Gulf of Mexico.
On our inaugural expedition in February 2013, our tri-national team embarked on a research cruise off of Cuba's south coast in the Gulf of Batabanó to share knowledge and scientific methods, and to survey migratory shark populations. The expedition was organized by EDF Oceans’ Cuba, Science, and Shark conservation programs and led on-the-water by scientists from University of Havana’s Center for Marine Research (CIM) and from the Mote Marine Laboratory in Florida; with participation by a scientist from Mexico’s College of the Southern Frontier (ECOSUR).
Results from this expedition will be highlighted in a 3 part blog series. Today’s post focuses on sharing science in data-limited shark fisheries. It will be followed by stories about the partnership of fishermen and scientists and baseline data. Join the journey here and follow along this week!
The Story behind Sharks
Sharks are top predators, critical for maintaining the health and resilience of marine ecosystems. Unfortunately, some shark populations are in trouble, primarily because more sharks are fished than are reproduced. Across the Gulf of Mexico, migratory animals such as sharks, tunas and others are an important source of food and economic activity. Sharks are threatened by overfishing and some populations in the Gulf of Mexico are estimated to have declined over 90% in the last 25 years.
Because they are migratory, many shark species traverse political boundaries. This makes monitoring their population status difficult and presents challenges to maintaining healthy stocks and rebuilding depleted ones. Many shark fisheries are considered “data-limited,” with little available information to assess the stock, including basic statistics covering reproduction, life span, migrations, abundance, and amount landed — both from targeted fishing and accidental catch – known as bycatch.
Eighty percent of all fisheries biomass and the vast majority of stocks in most countries are data poor. Fortunately, scientific techniques exist to help assess fisheries with minimal data. EDF’s Oceans science team is advancing assessment methods that use easily gathered data or pre-existing information. The key to assessing data-limited fisheries is to have access to any available fishery data (for example, catch at sea or at a landing site) or to fishery independent surveys (for example, monitoring of shark size, sex and abundance). Depending on the method used, a data-limited assessment estimates the current population’s sustainable catch, risk of overfishing, or stock status – how healthy the stock is at current fishing levels. The first step to take advantage of these new data-limited assessment methods is to pull together any available data and improve monitoring.
Although some shark populations in the Gulf of Mexico are well studied and the U.S. has conducted comprehensive assessments, more data is needed on migratory shark species throughout the region. EDF and our partners are taking the first steps to help determine the status of populations. Toward this end, EDF established a tri-national partnership for monitoring and management of shark fisheries among scientists in Cuba, Mexico and the United States. Scientists are working together to collect and organize information on shark catches from fishing ports and aboard fishing vessels, as well as conducting biological monitoring surveys across a diverse array of habitats apart from shark fishery catch. The partnership has reached agreement with INAPESCA, Mexico’s national fisheries research institute, to standardize shark monitoring methods across all of its Gulf States. Scientists from Cuba’s Center for Marine Research (CIM) are building a shark database and working with partners in Mexico to incorporate their data. All of these steps will aid in future assessments, setting conservation goals and sustaining populations and fisheries in the Gulf of Mexico. These efforts are the backbone of a successful shark recovery program.
The Expedition Begins!
Off the southwest coast of Cuba, lie the waters of the Gulf of Batabanó which extend out to the Isle of Youth along with several nearby small islands and cays lining the southwestern edge of the Cuban shelf and into the Gulf of Mexico. A team of 16 researchers from Cuba, Mexico and the U.S. boarded the University of Havana's Center of Marine Research (CIM) research vessel the RV Felipe Poey at the port of Batabanó for nine days of shark exploration, February 10-19, 2013. The goal was to sample shark populations, research plankton populations and examine sea floor sediment for populations of small mollusks, worms and crustaceans. During the expedition the team sampled an array of marine habitats, enabling researchers to study shark-habitat associations within the Gulf of Batabanó shelf and flats, inner island groups, near the coast and adjacent coral reefs off the Isle of Youth. One of the main objectives of this cruise was to survey the region to understand which species are present, search for “hotspots” where animals are especially abundant, and tag sharks for migration studies. Additionally, researchers shared information about catch records from fishing ports in the Northern portion of Cuba. Dr. Bob Hueter and Jack Morris from Mote Marine Laboratory trained their counterparts in shark species identification, shark capture -and-release methods, tagging techniques and other aspects of shark biological research.
Preliminary data from CIM had shown that sharks are present in the upper Gulf, as well as around the Isle of Youth, but increased monitoring across different habitats throughout the year is needed to assess current species abundance. Researchers from the University of Havana are monitoring Cuba's shark populations along the Gulf Coast and will continue to census sharks in and around the Gulf of Batabanó. In the meantime, Mote Marine Laboratory researchers are assessing populations of sharks off Florida’s west coast, and partners in Mexico are expanding research to study shark nursery areas, shark catch and migration patterns in coastal waters off Mexico. All of these monitoring efforts will improve the quantity and quality of data and enable a tri-national assessment of shark population status, including mapping migration routes throughout the Gulf of Mexico and Caribbean.
Conservation efforts in the Gulf and Caribbean require collaboration from the United States, Mexico and Cuba. Scientists, not just sharks, are crossing borders. Collecting and sharing data is critical to developing a better understanding of fisheries and to designing innovative management programs to save these species and improve the livelihoods of fishermen and fishing communities in each country. EDF and our partners look forward to strengthening and expanding our partnership in the coming years.
 Baum JK, Myers RA. Shifting baselines and the decline of pelagic sharks in the Gulf of Mexico. Ecology Letters 2004; 7: 135–45.