Issuu

Puerto Rico Sea Grant Progress Report

Submitted: November 20, 2019

-Title: Ciguatoxin detection and model predictions for use in fisheries management in Puerto Rico

-Name and affiliation of researchers:

Joseph J. Luczkovich AFFILIATION: Department of Biology, East Carolina University, Greenville, NC, 27858 luczkovichj@ecu.edu 252-328-9402

Cynthia Grace-McCaskey AFFILIATION: Department of Anthropology, East Carolina University, Greenville, NC, 27858 gracemccaskeyc15@ecu.edu

David Griffith AFFILIATION: Department of Anthropology, East Carolina University, Greenville, NC, 27858 griffithd@ecu.edu

Miguel Del Pozo AFFILIATION: University of Puerto Rico - Ponce, Miguel.delpozo@gmail.com

Results and findings

Interviews with fishers

Using open format interviews with fishers, ciguatoxin (CTX) “hotspots” were identified via TEK (Traditional Ecological Knowledge) on Puerto Rico (south coast of Puerto Rico from Ponce east to Maunabo, south coast of Vieques, east coast of Vieques, south coast of St. Thomas). We are in the process of confirming these “hotspots” in two ways: 1) with CTX toxicity measurements (these samples are being processed now with the mouse neuroblastoma N2A bioassay) of fish tissues that we collected in March - June 2019 and October 2019; and, 2) with Gambierdiscus sp. collections taken with screen rig collectors at the “hotspots” and “cold spots” (October 2019). We interviewed fishers at fish houses and marinas in Fajardo, Naguabo, Maunabo, Guayama, and Ponce on Puerto Rico and Charlotte Amalie on St. Thomas USVI. A summary of these interviews indicated that most CTX “hotspots” and ciguatera fish poisoning cases were on the southern side of the islands of Puerto Rico, Vieques, and St. Thomas, USVI. The fish species with ciguatera named by fishers are in the families Carangidae (jacks), Sphyraenidae (barracuda), Lutjanidae (snappers), Labridae (wrasses, including hogfish), Serranidae, and Epinephelidae (groupers).

CTX testing in fish tissues

We have now collected fish tissues from these species and others at several trophic levels, both from samples obtained at the fish houses and from fishes speared or caught hook and line at “hotspot” and “coldspot” areas identified in the TEK interviews. We have fish tissue samples from 110 individual fish, with various tissue samples were taken from each fish including epaxial muscle, liver, gonads, and stomach contents taken. These fishes are all from Puerto Rico in TEK-reported “hotspots” and other “cold spots” (places where fishers have harvested and sold fish in the past without any ciguatoxin or fish poisoning reports). Hogfish and great barracuda tissues were obtained at both “hotspot” and “coldspot” ciguatoxin areas. Preliminary data from N2A mouse neuroblastoma assays conducted at the ECU Brody Medical School to date indicate that hogfish and barracuda were toxic at the hotspot areas only (fish obtained directly from fishers in Guayama, PR on the south coast); most neuroblastoma cells exposed to these fish tissue extracts were killed. Hogfish were obtained from fish houses in

Naguabo, cero was obtained from a fish house in Manaubo, and dog snapper, southern sennet and great barracuda (Sphyraenidae) were obtained from a fisherman in Fajardo (all fish taken from the coldspot areas); testing with N2A bioassay showed these were non-toxic or less toxic; few or no cells were killed. More fish tissues will be tested (n = 16 fish have been tested for CTX so far), but it is too early to characterize the results statistically at present, as further fish tissues must be processed and calculations of CTX concentration for each tissue type (in ppb) for each species and each trophic level in the hotspot and coldspot areas must be completed. Actual concentrations in ppb of CTX is still being determined and will be reported in a future report.

Dinoflagellate Gambierdiscus sp. sampling

Screen collectors deployed for 24-hours at the “hotspot” and “coldspot” areas were collected during dive trips in October 2019, preserved at UPR Humacao Figure 1 The Gambierdiscus cells from these collections are being counted and strains of Gambierdiscus sp. are being identified now by scientists at the NOAA Beaufort Laboratory. Gambierdiscus sp. cells were positively identified in a preliminary microscopic inspection of the samples from the hotspot areas taken immediately after collection in October by Sylvia Velez (UPR Humacao) and Chris Holland (NOAA Beaufort Laboratory) Figure 2.

The above preliminary results and a participant-derived map of “hotspots” and “cold spots” for this region of PR and USVI have been developed in Google Earth for dissemination to users and managers (Caribbean Marine Fisheries Council meeting scheduled for Dec 11, 2019).

Methods used

Open-ended TEK interviews were conducted at fish houses and marinas in St. Thomas and Puerto Rico with approximately 20 fishers in Puerto Rico and another 14 in St. Thomas USVI (34 total). Google Earth was used to plot the CTX hotspots and “cold spots” from participatory mapping data obtained during the TEK interviews.

Fish tissues were sampled during the visits to fish houses during March – June 2019 and during field collections made while diving on Puerto Rico reefs in Oct 2019. Samples were obtained by

Figure 1. Luczkovich deploying screen rigs in Oct 2019. Photo credit: Dave Sybert, ECU

Figure 2 Gambierdiscus sp. collected on screen rig at hotspot area in Oct 2019 (Photo credit: Sylvia M. VélezVillamil, UPRH)

purchasing market fish or by collecting fish that are not typically harvested (e.g. Great barracudas acquired by special request); tissue samples were obtained from muscle, liver, and head regions. Frozen samples of great barracuda, hogfish, cero, king mackerel, and other species were returned to ECU and are undergoing laboratory toxicity testing now (CBA-N2A mouse cell bioassay). We sampled Gambierdiscus sp. using screen collectors placed at two depths (60’ and 90-100’) by divers on the reefs in “hotspot” and “coldspot” areas. We will obtain more fish tissue and gut contents in future visits to Puerto Rico in the upcoming year.

-Objectives

1. To determine where CFP toxic sites are and identify uncontaminated sites. (90% completed)

2. To collect parameters (cell counts of Gambierdiscus sp., fish species diet data) for an ECOPATH food web model at these sites. (50% completed)

3. To predict levels of CTX at each trophic level and by fish species within these areas using the ECOTRACER simulation routine within ECOPATH and validate these simulations with observed data for Puerto Rico. (50% completed)

4. To provide to Puerto Rico Sea Grant (PRSG) educational staff the data from our validated ecosystem model results and measured ciguatoxin levels in species of fishes targeted by subsistence and sport fishers to be used in education and outreach efforts. (0% Completed)

-Other products

A map of the ciguatoxic areas derived from TEK interviews (Figure 3).

Figure 3 A preliminary map of hotspot and cold spot areas derived from TEK interviews with fishers is provided. Also indicated are the fish houses where interviews were conducted and fish samples obtained. Finally, also shown are the sampling locations

(CTX-1 and CTX-2 in the cold spot areas near Naguabo, PR and Fajardo, PR and CTX-3 and CTX-4 in the hotspot region (near Guayama, PR)

-List PI’s supported

Joseph J. Luczkovich, ECU, PI, 0.5 person-months

Cindy Grace McCaskey, ECU, co-PI 0.5 person-months

Miguel Del Pozo, UPR Ponce, co-PI Subcontractor: $11,192.41

David Griffith, ECU, co-PI, no support provided by Sea Grant

-List students supported

Henry Raab, (609) 287-4797, raabh14@students.ecu.edu, PhD in Coastal Resources Management, paid by SG $14,000 and $14,000 by ECU as match

2. RELEVANCE ‐

Ciguatoxin is a serious human health issue in tropical areas where people consume reef fishes. Ciguatera losses in the US are estimated at $15 to $22 million annually due to increased hospitalizations, lost work and lost fisheries. Globally, there are about 25,000 - 50,000 cases reported annually, with many of these cases occurring in Puerto Rico and the USVI alone (Tosteson,1995). Though we know a good deal about the actual CTXs found in fish, we know relatively little about how these toxins accumulate in food webs. Currently, prediction of the time course of a ciguatera outbreak, the species involved, and the locations where it might be most common are difficult for fishery managers and seafood dealers. Our mapping effort will help predict these ciguatera areas and the ECOPATH model will produce a time course after an algal bloom is detected.

3. RESPONSE –

We mapped CTX hotspots in Puerto Rico and St. Thomas, US Virgin Islands. The partners were the co-PIs, scientific staff at University of Puerto Rico at Humacao and various key informants from the commercial and recreational fishing sector and seafood dealers in the region with expert knowledge of the fisheries and species involved. The maps produced in association with these partners will be presented to the Caribbean Fishery Management Council at the next council meeting in December 2019 The CTX bioaccumulation in food web model is still in development, awaiting the cell counts and CTX levels of various fishes.

4. RESULTS

The fishers and seafood dealers interviewed recognize the significance of the problem as their customers, and their families, and they themselves have been directly affected. Some people interviewed have experienced symptoms during their entire lives and even reported symptoms to us during the time of our fieldwork, indicating there is a continuing problem with CTX occurring in fishes. CTX is not observable until the fish is consumed, so given the continuing demand for seafood and the unpredictability of the toxin in the tissues, our approach is likely to improve the detection and prediction of ciguatera in the Caribbean. People are getting sick and perhaps dying from ciguatoxin in seafood as we are developing this model. It is urgent to complete our studies as quickly as possible and get a surveillance program started in the region. In addition, consumers of tropical fish around the world will benefit from this research with a lower risk of ciguatera, as some CTX has been detected in fishes exported to Europe and throughout the USA Our findings will shed light on a poorly understood illness