FISHBIO: Fisheries research, monitoring, and conservation

June 7, 2013

ocean

There’s no denying two things about our world’s oceans: 1) they are really big, and 2) they’re a really big deal. The big, blue, vastness of the oceans cover more than 70% of our planet’s surface. Some would therefore make the case that our planet ought to be named “Ocean” rather than “Earth.” In honor of World Ocean’s Day tomorrow (June 8) we wanted to highlight some of our marine-themed blog posts to show how important the oceans are to anyone who cares about fish, water, or the environment.

The ocean is home to an incredible diversity of fishes. More than 15,700 species of marine fishes have been described, and scientists estimate another 4,000 species await discovery (Mora et al. 2008). This colorful array spans a range of body forms as unique and varied as the ocean sunfish (see Ocean sunbathers), the Pacific viperfish (see Got teeth?), the longnose lancetfish (see Washed up), the salmon snailfish (see Jabba the Hutt?), the spiny lumpsucker (see Cute or ugly?) – and who could forget the blob sculpin (see The old man in the sea)? This parade of evolutionary diversity only scratches the surface of what we know about the ocean and its inhabitants — so much about this watery world remains to be explored, discovered, and understood.

Physical processes in the ocean fuel the food web that sustains marine life (see Wind-powered), and play an important role in the lives of salmon that spend a few ocean-going years fattening up (see Salmon Hunger Games). Migrating salmon are the perfect ambassadors to show us how the watershed connects land and sea, as freshwater flows to saltwater. However, this connectivity also creates problems when runoff water gathers toxic chemicals and pollutants from land and carries them to sea (see Toxic runoff). Our oceans face a host of other threats, from fisheries in decline (see The latest tuna fad) to changing ocean chemistry from the excess of carbon dioxide in the atmosphere (see Ocean acidification). One way to help preserve the ocean’s important species and habitats is to designate special places as marine protected areas, creating healthy ecological savings accounts to help marine life weather future changes in ocean conditions. It’s also important to remember how important the oceans are to our daily lives, from supplying the air we breathe to the water we drink. We can reflect on how our actions on land can impact the waters far from our shores, and try to make positive changes — on World Ocean Day, and every day!

Tags: fish species diversity, ocean

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Marine, Salmon

Wind-powered

April 5, 2013

Spring has officially arrived, the periods between rains are getting longer, and sunny, clear days are becoming more numerous, enticing visitors and residents of the northern California coast to engage in outdoor activities. A frequent companion during such pursuits is the cold, strong, steady wind. Blowing from the north, this seasonal wind pattern pushes massive quantities of near-shore ocean water along the coast, deflecting it westward and away from the shoreline through a process referred to as Ekman transport.

As the surface water moves away from the shore, cold, nutrient-rich water from the deep ocean moves up to replace it. This process of upwelling supplies the nutrients that support the base of the highly diverse and productive food web of the California Current. The strength and duration of this spring upwelling varies from year to year, resulting in differences in food supply and transport to nearshore waters. Such variability can cause cascades throughout the food chain. For Chinook salmon, this means that when their outmigration to the ocean coincides with favorable upwelling conditions, the smolts’ novel hunting grounds can be a rich smorgasbord of crustaceans and forage fish, fostering good survival and growth (see Salmon hunger games). When ocean conditions are less favorable, salmon populations dwindle.

The impact of poor ocean conditions on salmon populations was particularly pronounced in the Central Valley several years ago, where populations are already subjected to a host of additional stressors, and a population crash lead to fishing closures in 2008 and 2009. As the stocks show signs of recovery and commercial and recreational pursuit of ocean Chinook salmon is permitted once again, the same wind that drives productivity of our coast will frequently keep salmon anglers confined to the docks during the eagerly awaited salmon fishing season. For the fish at least, the wind appears to have multiple benefits.

Tags: food, ocean, Upwelling

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Conferences and Events, Fish Report, Marine

Ecological savings accounts: Marine protected areas

March 11, 2013

Underwater state parks. Ecological savings accounts. Noah’s Arks. These were all terms used to describe marine protected areas (MPAs) at the State of the California Central Coast Symposium recently held in Monterey, California. The symposium highlighted research conducted during the five years since California embarked on an ambitious mission in 2007: to establish a coordinated network of ocean areas off-limits to some or all fishing along the entire state coastline. At times controversial, the stakeholder-driven process came to a close last fall when the northernmost, final links in the MPA chain went into effect from Mendocino County to the Oregon border. The Monterey symposium focused on the first section of the MPA network established on the central coast from Pigeon Point to Point Conception in 2007. California’s statewide MPA network is the first of its kind in the country, and other states like Oregon are hoping to follow suit.

“The state of California is recognized as the leader in the design and implementation of MPAs,” said marine scientist Mark Carr from UC Santa Cruz who has played a large role in process. With people around the world watching California’s MPA experiment with interest, Carr said he and other scientists feel a serious responsibility to monitor and evaluate how these conservation and management tools perform. Some of the goals of these protected, “ecological savings accounts” are to serve as refuges for populations of fish, kelp, crabs, and other species to recover from exploitation, to allow older fish to reproduce and help sustain fisheries outside reserve borders, and to provide insurance against changing ocean conditions like those caused by climate change. For the past five years, researchers from around the central coast diligently surveyed the health of the ecosystems inside and outside the central coast MPAs. They measured abalone-like limpets clinging to rocks in the wave splashed intertidal, enlisted the help of volunteer anglers to catch and release fish, and explored the shadowy depths of the MPAs with submarines and camera-equipped robots hundreds of feet below the surface.

So far, their findings are promising. Many species, from black rockfish and lingcod to owl limpets and black abalone, have increased in abundance inside the new MPAs over the past five years. Some species of fish are also larger inside the protected areas, and these larger fish can produce more offspring. A report compiled by the California Ocean Science Trust summarizing these and other scientific findings of MPA monitoring is available as an interactive e-book on the new Ocean Spaces website. One of FISHBIO’S biologists also presented at the symposium, discussing her graduate research studying the feeding habits of gopher rockfish inside and outside of the central coast MPAs (see Gopher (rockfish) guts). These initial assessments of the MPAs are just a prelude of changes to come, as ecosystem recovery can take decades to occur. In addition to their ecological benefits, protecting special coastal places for their intrinsic value makes economic sense. California’s renowned and much-visited coastline is a huge driver of the state’s ocean economy, worth about $42.9 billion (Kildow 2005). Some symposium speakers stressed that that the economic value of MPAs need be studied explicitly going forward. But from many angles, it appears that this investment in marine conservation is already paying off.

This post featured in our weekly e-newsletter, the Fish Report. You can subscribe to the Fish Report here.

Tags: Conferences, Conservation, marine, Marine Protected Areas, ocean

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Conferences and Events, Ecology, Marine, Other Fish Species, Research

Gopher (rockfish) guts

March 8, 2013

We know the importance of studying what fish eat when it comes to the feeding habits of salmon predators (see What’s for dinner, Last meal, Survival of the biggest). But did you know you can even get a graduate degree studying fish guts? That’s what one of our biologists did. She recently presented the results of her master’s thesis at the State of the California Central Coast Symposium on Marine Protected Areas in Monterey, sharing her research on the diet of the gopher rockfish (Sebastes carnatus). As you can see from the top photo, these fish scarf down quite a smorgasbord.

Gopher rockfish are one of about 60 different species of rockfishes in the genus Sebastes found on the California coast. Rockfish come in an array of colors and are known for their venomous spines, which can pack a stinging poke for an unwary angler. As generalist predators, gopher rockfish eat a diversity of other animals, from crabs, to worms, to fish. In this study, the gopher rockfish was used to study changes that might happen to the food web inside and outside of marine protected areas (MPAs) in central California. Results showed that gopher rockfish diets didn’t differ much inside and outside of these new MPAs, but fish caught at different locations along the coast ate different things. This is likely due to different habitats at these locations, ranging from Año Nuevo to Point Buchon near Morro Bay, which can result in differences in the invertebrate community. The gopher rockfish’s most important prey included brittle stars (a type of sea star), crabs, mysids, and shrimp (Loury 2011).

A gopher rockfish’s last meal is a bit like a window into the community where it lives, which is otherwise difficult to survey. Gopher rockfish often live in rocky holes – similar to a certain small mammal that shares their common name. While SCUBA divers can survey nearshore marine areas to count larger animals, they usually don’t count the many small critters hiding in cracks and crannies. A hungry gopher rockfish can more effectively “sample” these spots. Studying fish diet is a bit like being a detective or an archaeologist, and sometimes you make surprising discoveries (see Opportunistic Meal). The strangest thing found in a gopher rockfish stomach? A handful of strawberry sea anemones. Those might have been an accidental snack – the fish was probably after a brittle star lodged in the anemone clump.

Tags: Conferences, Diet, marine ecology, marine fish, Marine Protected Areas, ocean, Predation, Research, rockfish

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Marine, Other Fish Species

Ocean sunbathers

December 26, 2012

Making forays to the deep ocean several times a day, munching on jellyfish, and basking at the water’s surface where gulls and cleaner fish can pick off your parasites: the ocean sunfish has figured out a pretty good life. And it has sweet scientific name (Mola mola) to boot. Although the ocean sunfish may look oddly prehistoric, it’s actually one of the most highly evolved fishes—meaning it has drastically changed from its ancestral form. Which makes sense, considering this fish doesn’t really have a tail, just a little rudder in the back called a clavus. Ocean sunfish take the prize as the heaviest bony fishes in the world: they can grow up to 10 feet in length and can weigh close to a staggering 5,000 pounds. Amazingly, they reach these beefy proportions eating a mostly gelatinous diet of jellies, squid, small fish, and crustaceans.

But even such behemoth fish face threats. Commercial fisheries don’t usually target these huge, slow swimmers specifically, but the sunfish often get trapped in fishing nets anyway. Ocean sunfish alone comprise 29% of the bycatch, or unintended extras, caught in the swordfish drift gillnet fishery in California (Cartamill and Lowe 2004). And before they can grow to megafish sizes, juvenile sunfish may fall prey to rowdy California sea lions. The raucous, barking California icons often rip the fins off small sunfish and even fling them around like Frisbees. That’s probably what happened to this little guy that FISBHIO technicians found on the beach in Monterey (above). Visitors might prefer seeing live sunfish at the Monterey Bay Aquarium, one of the few places in the world that display these open ocean wanderers. But stumbling across the dead little ones washed up on shore is a reminder of how nature works—and that in a fish’s world, growing up is hard to do.

Tags: bycatch, ocean sunfish, sunfish

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Commercial Fishery, Fish Report, Marine

The latest tuna fad

December 10, 2012

Similar to bugs buzzing around a light in the dark, fish will flock to a floating object or structure in the vast emptiness of the open ocean. The tuna industry has learned to exploit this behavior to make tunas easier to catch with the help of Fish Aggregating Devices, or FADs. Whether it’s a large, bobbing buoy anchored to the sea floor or a long, drifting net attached to a satellite beacon, a FAD lures fish to a localized area. A fishing boat can then encircle the FAD with a net like a purse seine and scoop up everything underneath (see video below). FADs have generated controversy in recent years because of their increasing use–and the fact that they just work so well.

Researchers recently announced that the estimated number of FADS in the ocean ranges from 47,000-105,000 (Baske et al. 2012). Some scientists and managers worry about these large numbers because they fear the devices make it too easy to overexploit already struggling tuna populations–like fishing in a barrel. Of particular concern in the Pacific Ocean are the juvenile bigeye tuna (Thunnus obesus) that tend to congregate around FADs (Lennert-Cody et al. 2008). Catching large numbers of these young fish that haven’t had time to reproduce makes it difficult for the population to recover. FADs also attract many other species besides tuna, and fishing nets indiscriminately ensnare them all, leading to the unintended deaths of animals like sharks, sea turtles, and billfishes.

The issue of FADs divided attendees at the recent meeting of the Western and Central Pacific Fisheries Commission, a multinational organization that manages tunas in the Pacific Ocean. Some hoped to increase the current three-month annual ban on FADs in the Pacific (July to September) to four months, but others argued an extension would hurt the fisheries of small Pacific nations. In the end, the Commission decided to extend the ban to four months. The fishing industry is not currently required to report their use of FADs, and many scientists are concerned about this lack of oversight. Researchers want to know how many FADs are out there, and when, where, and how they are being used, to better understand their impacts on tuna and other species. Though the popularity of these devices is on the rise, some hope this is one fad that will quickly go out of style.

This post featured in our weekly e-newsletter, the Fish Report. You can subscribe to the Fish Report here.

Tags: Commercial Fishery, Tuna

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Marine

Got teeth?

September 12, 2012

When Pacific salmon, in particular males, undertake their final spawning migration they develop rather fearsome sets of teeth, which they may use to defend their spawning territory against competitors. Though impressive, salmon teeth can’t hold a candle to some of the largest fangs (relative to body size) in the animal kingdom, which belong to species in the family Stomiidae (viperfishes and dragonfishes). The Pacific viperfish (Chauliodus macouni), pictured below, is a deep-sea predator that occurs in the North Pacific from the Mexican coast to Japan in depths of up to 5000 meters (16,405 feet).

In a world where food is generally scarce and predators can hardly afford to miss a meal, large teeth and long, hinged jaws that appear out of proportion to the rest of their body allow viperfish and other deep-sea predators to capture and swallow both large and small prey. Remaining concealed in the twilight of the ocean depths during the day, Pacific viperfish often ascend to surface waters (less than 200 meters, or 656 feet) at night where food is more plentiful (Willis and Pearcy 1982). When the opportunity presents itself, they use their impressive dentition to capture crustaceans and other small fishes (such as lanternfish and other viperfish; Yang 2011).

Viperfish lack a gasbladder to regulate their buoyancy and instead they have deposits of gelatinous tissue, high in water content, that allow them to remain suspended in the water column with minimal energy expenditure (Yancey et al. 1989). It is likely that their ventral photophores (the small light-emitting organs along their bottom half, barely visible in the photo above) match the penetrating light from the surface and camouflage them from other predators that may be lurking below.

As is the case with so many oceanic species, in particular those that occur in deep waters and are not commercially exploited, very little is known about these fascinating creatures. What we do know, however, is that we are glad that salmon don’t have teeth of viperfish proportions, or our in-river surveys would be downright scary!

Tags: Teeth, Viperfish

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Fish Report, Marine

Unlocking the mysteries beneath the surface

September 10, 2012

As the Deepsea Challenger, powered by the well-known film director James Cameron, touched bottom in the deepest part of the ocean back in March, the possibilities for discovery in the underwater world became seemingly endless. It is estimated that the ocean supports roughly 50 percent of all species on earth but more than 95 percent of the ocean is yet to be explored, and there is no telling what else is out there to be discovered. The Deepsea Challenger’s voyage was not the first time humans have made the descent 36,000 feet below the surface, but advancements in technology have made it possible to stay on the ocean floor for a longer period of time to collect scientific samples and videos. The more we can learn about life under the surface, the better we can understand and manage our marine resources.

The report A Census of Fishes and Everything They Eat: How the Census of Marine Life Advanced Fisheries Science published in Fisheries magazine highlights the importance of managing the ecosystem as a whole instead of from the standpoint of a single-species fishery. The first Census of Marine Life was an international, decade-long effort (2000-2010) by over 2,700 scientists in more than 80 countries who study marine biodiversity. There are roughly 16,764 marine species that have been verified (as of Feb. 19, 2010) by California Academy of Sciences and it is estimated that there are still another 5,000 species to be discovered, each one dependent on another for survival. As we begin to understand the rich diversity beneath the surface, we can better manage populations of fish such as forage fish, which are an important link between the biomass of the lower trophic level to that of the upper trophic level in the food chain. While they are just as important as the prized salmon and tuna, management is difficult because many believe that the calculated predation rates and commercial harvest is often underestimated.

Throughout history, humans have looked to the sea as an important source of protein. In fact, further results of the census revealed that humans have impacted local fish stocks longer than previously believed, but these negative impacts have been on the rise in the last century. Overall, the census proved to be effective in gathering vital information, evaluating current issues and identifying areas lacking research in marine science. It even helped to advance fish monitoring technologies. However, it also proved that there is still much research to be done. For example, areas such as seamounts (undersea mountains) provide nutrients and habitat for much of the ocean’s marine life and yet very little is known about many of the seamounts in existence. As continued exploration reveals how much more is yet to be discovered, it’s clear that ongoing research gets us closer to understanding the world beneath the surface, and to developing technologies that allow us to follow fish further into the deep.

This post featured in our weekly e-newsletter, the Fish Report. You can subscribe to the Fish Report here.

Tags: Marine Census

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Marine

Ocean acidification and pacific fish

August 6, 2012

Since the 1970s many people have become familiar with the concept of acid rain and its negative effects on the environment, but fewer are aware of the impacts of fossil fuels on the chemistry of the ocean and the potential consequences on valuable fisheries resources. Ocean acidification is the common term for several chemical reactions that occur when carbon dioxide (CO₂) released into the atmosphere is absorbed by seawater. The reactions reduce the carbonate ion concentration and increase the hydrogen ion concentration, making the seawater more acidic. The concentration of carbonate ions in the ocean determines the precipitation of calcium carbonate minerals (e.g., aragonite and calcite), which are used by marine organisms such as oysters and clams, to form their shells or skeletons through calcification. Most ocean surface waters are supersaturated in calcium carbonate minerals, but at lower pH, waters can be undersaturated with these vital minerals.

Since the Industrial Revolution began, there has been a 30% increase in the acidity of the ocean, and based on estimates of carbon dioxide emissions the acidity of the surface waters could rise by 150% by 2100. Recently, a high-resolution computer model was developed to estimate the ocean acidity in the California Current System over the next few decades (Gruber et al. 2012; Figure 1). Results of the simulations indicate that acidification could have considerable impacts on the Pacific Ocean off the West Coast of the U.S. The coast off California is an upwelling zone where winds push surface waters offshore and cause deeper ocean water, naturally high in levels of dissolved CO₂, to rise to the surface. The combination of surface waters low in pH (due to upwelling) and aragonite undersaturation makes the California Current System particularly susceptible to ocean acidification.

Figure 1. Animation of changes in ocean acidification over time in the California Current System. The left side shows the depth of aragonite saturation, and the right side shows the surface ocean pH. Courtesy of Nicolas Gruber and Claudine Hauri. (click to view animation)

The rise in ocean acidity is clearly a concern for the West Coast shellfish industry, which relies directly on aragonite-secreting organisms such as oysters, but this shift in ocean chemistry could also have significant impacts on West Coast salmon populations. Pteropods are small free-swimming mollusks that form a vital link in marine food webs, and are an important food source for juvenile salmonids in the northern California Current (Brodeur et al. 2007). The shell production of pteropods is sensitive to decreases in pH (Comeau et al. 2010), and at a certain pH, their calcium carbonate shells will actually dissolve (see photos at NOAA). Results of the computer model found that within the next 30 years, long stretches of the California central coast surface waters are projected to be undersaturated in aragonite all summer long, which could have substantial impacts on organisms such as pteropods and their salmonid predators. Researchers are just beginning to understand the potential effects of ocean acidification on the marine ecosystems (Le Quesne and Pinnegar 2012), and each study adds new insight into the complexity of the relationship between water chemistry and ocean food webs.

Tags: Ocean acidification

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Marine

Washed up…

August 1, 2012

This ferocious looking sea creature is the longnose lancetfish, Alepisaurus ferox (from the Greek, meaning “lizard without scales”), which FISHBIO staff have come across during past travels. Growing to a length of over two meters (6 ½ feet), lancetfish prowl the seas in waters over a thousand meters deep, feeding on fishes, squids and crustaceans (Fujita and Hattori 1976). Lancetfish are frequently caught as bycatch in the tuna longline fishery, although they are not commercially exploited or marketed due to their flabby, white meat. Not only does their white, soft muscle tissue prevent them from being targeted for consumption, but it also implies that they are incapable of sustained swimming at high speeds. Therefore, most of their diet consists of slow moving prey (including lumpsuckers, lanternfishes and juvenile lancetfish; Kubota and Uyeno 1970). In the pelagic, open ocean, environment it is hardly possible to use ambush tactics, owing to the lack of natural cover, but their counter-shaded body (dark on top, light on the ventral side) and high maneuverability (suggested by their large dorsal fin) allow them to lie nearly invisible in the water column and occasionally capture fast swimmers (even juvenile tunas, swordfishes and salmon; see Romanov and Zamorov 2002).

Despite the worldwide distribution of longnose lancetfish and their relatively high abundance, very little is known about the biology of this species. Some evidence indicates that they may be synchronous hermaphrodites, possessing both male and female reproductive organs (Smith and Atz 1973), yet the specific mode, timing and even location of reproduction remain largely unknown. Though not rare, these pelagic predators are seldom seen alive in nearshore waters, but occasionally wash up dead or dying on the shores of all the world’s oceans. The reasons for these occurrences are generally unknown, but may include weakness resulting from high parasite loads, ingestion of non-food items such as plastics, and natural severe changes in oceanic conditions (Kubota and Uyeno 1970, Orlov and Ul’chenko 2002). So next time you take a stroll on the beach, be sure to keep a sharp eye – you might just be lucky enough to come across one of these fascinating creatures.

Tags: longnose lancetfish

Planet ocean

Wind-powered

Ecological savings accounts: Marine protected areas

Gopher (rockfish) guts

Ocean sunbathers

The latest tuna fad

Got teeth?

Unlocking the mysteries beneath the surface

Ocean acidification and pacific fish

Washed up…

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