CPUE Think Tank – Monitoring Fish Catch in Fiji

Researchers gather as part of a think thank on catch per unit effort for Fiji.

Fisheries researchers gather for a CPUE think tank

Researchers from the Wildlife Conservation Society’s Fiji and Papua New Guinea programs, University of the South Pacific’s Institute of Applied Science, Department of Fisheries and Conservation International’s Hawaii program held a ‘CPUE Think Tank’ in Suva in October, 2015. CPUE stands for ‘catch per unit effort’ and it is used by fisheries managers to monitor fish catch to understand how fish stocks are changing over time.

A number of organisations including the Fiji Locally Managed Marine Area (FLMMA) network have been using a CPUE logbook with data going back as far as 2008. Some of this data have been collected by scientists, while others have been collected by trained community representatives. However, despite time, money and effort, much of this data has not been analysed and therefore not been used to guide or improve fisheries management.

Over the course of a morning, participants of the think tank shared some of the challenges they faced working with CPUE data when it came to collection, storage and analysis. We learnt that fishers in particular use more than one gear type on any given fishing trip, making it difficult to know what fish was caught by what gear type. Recording time spent traveling to a fishing site versus actually fishing was challenging for fishers (who naturally do not wear watches). There were also differences between local names and scientific names for fish and invertebrate species, and local names in Fiji can be highly specific to a geographic location. Participants of the think tank highlighted ways to improve the current logbook to make it easier to use, and to reduce errors made by recorders.

We also thought carefully about what types of management questions CPUE data can help us answer, and which ones were the most important for managers. Some of the key questions highlighted were:

  • Do specific gear types target specific fish groups?
  • How much fish being caught is below the legal size limit for Fiji?
  • What proportion of fish is eaten versus sold?
  • Economic values of fisheries for different villages/districts
  • What distances are fishers traveling to fish and how much time is spent fishing in general?

Over the upcoming months, WCS and USP will be analysing their data to try and answer some of these key questions, and providing more up to date information on how our coastal fisheries in Fiji are doing. We also will be assessing if CPUE surveys are worth investing in, and can they be used to improve fisheries management.

Words by Sangeeta Mangubhai and image by Dwain Qalovaki

Dropping in for a fish census

Special to WCS by science writer, Amy West

Ready to deploy the BRUV off the support boat

Ready to deploy the BRUV off the support boat

A curious visit by a human or motored robotic vehicle likely sends deep-water fish fleeing. It’s difficult to accurately tally fish if we appear as an ungainly and potential predator. In addition, the robot’s electrical field and narrow camera view may not reflect the actual fish composition. So dropping video festooned with bait that sits patiently on the bottom can harmlessly capture which fish are out and about.

 

An Australian duo from Western Australia University aboard the Waitt Institute research vessel has dropped nearly 60 of these camera systems, fondly called  “BRUVs” (baited remote underwater video). Todd Bond and Jordan Goetze have perfected the art of heaving these awkward rebar frames into and out of the water with sheer brute strength, and, well, the help of a cleverly rigged PVC and wooden winch thanks to the Waitt Institute crew. Angling the pair of cameras also allows length measurements of the fish. Needless to say, these boy’s fish ID skills are top notch.

Winching made easier thanks to the Waitt Institute crew

Winching made easier thanks to the Waitt Institute crew

“Hey what is that fish?” I ask trying to describe the coloration.

Coris aygula,” says Jordan without missing one beat.

“And that one on the…,” I ask.

Heniochus  acuminatus,” he says before I can finish my sentence.  Later a fish shoots across the pixelated television screen, totally unrecognizable to all of us. “That’s an jobfish!” hollers out Todd.

 

 

Dropping these frames along Fiji’s reefs or seamounts gives us a peek into the fish assemblages at deeper depths; which are essentially unexplored. Luckily for us the reef system provides natural ledges. Reefs worldwide will typically level out at roughly 30 meters and 60 meters, and some at 90 meters etc… These natural platforms form from erosion thousands of years ago when sea level stabilized, allowing centuries of wave action to eat away at the coral. When sea level rises or falls, a reef is normally dynamic: either building up or dying off.

 

Finding a ledge after 60 meters was challenging-- it just drops off.

Finding a ledge after 60 meters was challenging– it just drops off.

When the team could locate these ledges on the sonar, they were ideal for their camera frames since most of the reef is so sheer. But the systems can go missing or slip off the line. Their recent loss of two cameras to the deep blue was hard to swallow, but par for the course when tossing expensive equipment overboard beyond our reach. Knots may come undone, and gear can be ripped away by currents or snagged on the way up.

 

 

 

Reviewing the footage back on board reveal fish fighting for bait, groupers stopping in for a mouth cleaning at cleaner stations, and a black blotch emperor at ~50 m losing its colors when near the bait. The sea bream at 70 meters changed its colors and striped pattern, too. If they didn’t capture this metamorphosis on video, it could be challenging to identify these fish from a still image without their markings. On this trip the duo have seen more cod and emperor fish at 70 to 80 meters, which have been largely fished from the shallower depths. They’ve also seen fish that extend well beyond their range as noted in fish ID guides.

 

Checking to make sure the cameras stayed on and what fish they captured

Checking to make sure the cameras stayed on and what fish they captured

Recently Jordan and WCS used this video technique to conclude whether the marine protected area had an effect on sharks. These baited cameras inside and outside of Fiji’s largest protected area, Namena Marine Reserve, showed twice as many sharks in the shallow waters of the reserve. Their numbers are thought to be higher inside the safe zone because of the larger number of prey fish available to them.

 

 

Surprisingly it’s the selective practice of spearfishing that’s taken a toll on Fiji’s reefs. It’s too craggy and steep to cast nets on the offshore barrier reefs, but with the expanding market for fish, more poaching, more spearfishing at night, and more boats carrying spearfishers occurs. There’s hope though: fish may be more intelligent than we think. The idea of “deepwater refuges” is a relatively new concept, but an old simple observation made by many divers: more fish are seen below the limits of where they are fished. The BRUVs finally quantified that observation. By dropping cameras both inside and outside an established and newer marine reserve at five meters and 30 meters, scientists found that fish targeted by fishing were missing in the shallower areas, yet seen deeper. The types of fish found deeper were similar within and outside the two marine reserves, indicating depth can be a natural refuge.

 

Though these one-hour videos give just a glimpse into a tiny cross section of the ocean, over time the data can show trends to help manage marine life that are beyond our view.  It keeps the fish counters safe and dry, which the boys aren’t ecstatic about, but they know sacrificing underwater time means collecting more data. All they need to do is grab a cup of coffee and start shouting out fish names.

 

Amy West has traveled worldwide as a marine scientist, specializing in fisheries and deep-sea ecology. Now as a science communicator she brings stories about ocean realms to the public through radio, video, photography, and writing. She’s usually diving into adventurous stories that take her on or below the water.

Parrotfish help research traditional knowledge

I joined up with the research team on a Friday in Namalata village in the district of Kubulau. I have always had a keen interest in traditional knowledge, which is in danger of draining away, so this trip was my chance to help investigate whether and how it is being passed on to the next generation.

Team “Bubute” (named after the parrotfish that our interviewees were asked to identify) included Rachel (collecting data for her PhD thesis), Lai and Seini (graduate researchers from USP) and me trying to use my local connections and experience to explore traditional knowledge in these parts.

As Lai was wrapping the waka (kava root used to make the drink for traditional ceremonies), I worried that it would be turned against us – used for an early morning drinking session. This proved right next morning when we presented the sevusevu on the island of Navatu. As soon as Buli Navatu (the local chief) accepted our offering, he ordered for it to be pounded and served to us in the village hall – at 9.00 am on Saturday morning!

When we escaped the drinking, my first interviewee was a man who hailed from Ono-i-Lau in the Lau group of islands. He had married a woman from Navatu and lived there for most of his life. We talked about the different plants and their uses for medicine, food, to sell and for special occasions. I noticed he used most plants at home, rather than selling or donating them to village functions. My traditional links meant I was duty bound to joke that as he is not contributing to the village, maybe they should send him back to Lau without his wife!

The elders relate closely with seasonal weather patterns and know which crops to plant where and when. They will plant a certain species of uvi (yam) in certain weather at a certain time of year to ensure it is perfect to harvest for a feast at Christmas, New Year or a big i-sevu (presentation of root crops to the vanua or church). I now know that planting in July and harvesting the following March will give me the biggest yams (I made a note to take back to my village).

The next stage is to analyse the data and assess the links between traditional knowledge and natural resource management. Hopefully the results will help enhance the effective transfer and application traditional knowledge to meet current needs as well as providing for future generations.

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Notes from the field: periodic harvests

I thought I’d be tweeting and blogging away from the field – but alas, since Digicel installed a tower in Kubulau, Vodafone signal is but a figment of my imagination. So I am cut off from all forms of communication with the outside world – six days in, it feels like a weight has been lifted.

After 18 long months of slogging it in the office and pitching proposals non-stop to donors, we are finally back in the field for a new project. During the past few years we have been collecting information about the reefs to provide recommendations about where to set up no-fishing zones (or marine protected areas – MPAs) and monitoring their effectiveness over time. This trip is different – we have asked the village of Kiobo in Kubulau District to open their MPA to see what happens. “What!” the purists would yell, “Open an MPA? Are you crazy?” But the simple fact is that rural communities in Fiji routinely open their MPAs to provide food for social functions. This practice comes from a cultural legacy throughout Melanesia of creating short-term, no-fishing zones specifically so that they would be able to have a great harvest for a social event and redistribute the food as a show of wealth and status. Thus, even though most communities within the Fiji Locally Managed Marine Area network say that they want to have fish for the future, they also very much want to have fish for the present.

More and more frequently, there are expectations that the MPAs can provide a source of income whenever the community needs money to pay school fees, church fees, provincial levies, etc. This is leading to more intense and more frequent harvests from MPAs, and the fish just don’t stand a chance. Here is where we come in – our current project is evaluating how much you can extract from an MPA and still have sustainable fisheries for the future. We recognise that the MPAs in Fiji work best where cultural practice is strong – and if cultural practice demands occasionally opening an MPA, then we need to be able to offer some better guidelines about how much can be harvested besides just “don’t take all the biggest fish.”

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In the field with us this time is Jordan Goetze, a PhD student from University of Western Australia, whom I’ve recruited to look at the ecological impacts of harvesting MPAs for his doctoral research. On this trip, he is testing out a range of survey methods to see which ones best document the impact of a week-long harvest from the Kiobo MPA. Our WCS staff are collecting our standard underwater visual census data, which he will compare with before and after harvest surveys of the reefs using diver-operated video and baited remote underwater video surveys (BRUVs). The diver-operated video information is certainly more efficient to collect than our laborious fish and benthic counts, while the BRUVs potentially allow us to collect a better record of predatory fish that are often skiddish of SCUBA divers. At the same time, we have sent out WCS staff and a Masters student from the University of the South Pacific to conduct household interviews to find out what the local people are expecting from the harvest in terms of food and monetary benefits, and then we will resurvey them after the event to see how these expectations were met.

Conducting fieldwork in remote Fiji is always challenging. Today we are stuck in the village as the fuel hose for our dive compressor became shredded, thus preventing us from filling our dive tanks. Waisea and Akuila have gone to Savusavu in search of a replacement. The winds have been up, causing rather treacherous conditions mooring at sites. Under pressure to complete 4 dives a day, we often find ourselves returning to the village for a low tide swap of empty for full tanks, which must be lugged across hundreds of meters of intertidal seagrass and algal beds. And there is no rest for the weary in the evening – data must be entered, kava drunk, and special efforts made to conduct awareness presentations in the surrounding villages so they understand what they stand to gain from the information collected from these surveys. Full support of the local communities is crucial for this project to succeed, so it is worth the extra effort to haul our generator, projector and white sheet around to the various villages by boat, often in the dark, for evening presentations to ensure that everyone knows what is happening.

What will we find when the MPA is opened? Unfortunately, it looks as though the local reports of emboldened poachers encroaching on inshore fishing grounds may be true. We certainly did not see overly abundant fish life in the MPA, and invertebrates were few and far between. Yet, hopefully the men and women of Kiobo village will still be able to pull in a sizeable catch, which can provide them a modicum of income while allowing us to gather a piece of the puzzle to evaluate thresholds of impact. Keep your coconut wireless tuned for the results . . . moce mada. Stacy

Groupers spawning in Fiji’s paradise

Groupers spawning in Fiji’s paradise

The grouper monitoring program in Kadavu was started by Dr. Yvonne Sadovy and Rick Nemeth from the Society for the Conservation of Reef Fish Aggregations in 2008. Dr. Sadovy assembled an international team consisting of local fisheries officers and local and international scientists to monitor the number and type of groupers in the area.

The area is used by several groupers and many other species for spawning so it was established as a marine protected area (no-take zone) managed by the local village. The main grouper that spawn at the site and are being monitored include the Camouflage grouper (Epinephelus polyphekadion), Brown marble grouper (E. fuscoguttatus), Squaretail coralgrouper (Plectropomus areolatus) and Black saddle grouper (P. laevis).

The study team consisted of me, Brad Erisman a professor of Marine Biology at Scripps Institution of Oceanography in San Diego, California, USA and Rick Nemeth from the Conservation of Reef Fish Aggregation in the Virgin Islands. Our research was supported by Siwa, the dive master, and Tulala the boat captain. We dove three times per day for six straight days, and we saw a lot of groupers. On the first day of diving, Brad and I saw approximately 50-60 Brown marble grouper and a few small groups of Camouflage grouper and Black saddle grouper. Rick didn’t arrive until the next day, because he was delayed because of a hurricane that was passing by his home in the U.S. Virgin Islands.

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For the rest of the week, we did not see many Camouflage grouper or Brown marble grouper, which suggested that these fish were not spawning at the time of our visit. For the Camouflage grouper, we suspect they have spawned already, whereas the Brown marble grouper may have spawned just before we arrived (before the full moon). However, with each passing day, we observed more and more Black saddle grouper. Many of these fish were really large – more than 90-100 cm in length and weighing more than 10 kg. The largest ones took on a brilliant coloration with dark gray on their head, front and back of their bodies but with a large white stripe down the middle, a bright white belly and lips. After three years of working at this site, this year seems to have the highest count of Black saddle grouper. These fish would swim by other groupers, turning their bodies to the side and shaking their head violently back and forth. While we are not sure exactly why these fish were behaving this way, in other groupers this behavior occurs in aggressive behavior between males as well by males attempting court and spawn with a female. By the end of the trip, we estimated that there were as many as 135 Black saddle grouper in our survey area.

In 2010, Rick Nemeth had placed three acoustic receivers on the reef to record the presence of any tagged camouflage grouper as they move in and out of the area to spawn. The portion of the project related to the receivers was set to finish this year, so we decided to retrieve all the receivers this week as well.

Overall, the trip was a great success. The entire staff at the resort was wonderful, generous, and helpful to us throughout our trip. We were invited by the chief and the staff to take part in a kava ceremony, where we learned a lot more about the local communities and their resources. Of course, we also accomplished all our research goals for the trip. Hopefully, if we are lucky, next year when we return we’ll get to see the spawning of the Black saddle grouper.