Sex doesn’t have to be the first thing you think of when approaching the fish counter—but it should factor into your final purchase decision. And I don’t mean oysters-as-aphrodisiacs. Whether you’re planning a summer fish fry or succulent sushi dinner, choosing sex-friendly seafood options has never been easier—or more important.
For centuries, we have unknowingly contributed to major coitus interruptus in the deep. This is due to several factors. One is a misalignment between the way we fish, and the way fish and other marine life fornicate.. Other sources of romantic disruption beneath the waves include coastal development, growing plastic and chemical pollution, and climate change.
Near-celibate, orgy-loving fish are a vulnerable lot
Many marine species live a mostly-celibate life. For example, some grouper, snapper, and dozens of reef fish abstain from sex all year long—until one brief window in time when they get together for a massive orgy. These “spawning aggregations” may attract every breeding adult within hundreds of miles for a few days of wild and crazy sex. In species such as tuna, these annual reproductive romps may last several weeks; in salmon it’s often only a few days.
Since adults only gather to reproduce one time per year, success of a species depends on these oceanic orgies. And success of these orgies depends on their predictability—the party happens in the same place, at the same time, every year. This allows fish to reliably find one another to get it on. But this predictability also helps the fishers find the fish. Spawning aggregations around the world have been fished so hard that many no longer exist.
When so many fish gathered in one small location, it is easy and rewarding for fishers to just keep on fishing. Even as populations plummet, they will still catch enough fish to make the effort worth it.
Favored Love Hotels Are Under Attack
Besides fishing, coastal development can wreck havoc to popular love hotels of watery wildlife. Salmon, fighting their way upstream for a once in a lifetime chance to get lucky, not only have to leap waterfalls, but now must scale dams to make it to the shallow upstream pools. Once there, their favored pebbled bottomed streams are often covered in soft silt, runoff from deforested land. Such habitats are far less suitable for laying eggs.
Man-made bulkheads, jetties, and other coastline alterations similarly threaten preferred habitat of those species that enjoy sex-on-the-beach, such as grunion. As we shift the sands to suit ourselves, we change the slope, sand quality, and other shoreline features, which can make it more difficult for species including fish and sea turtles to lay their eggs in shallow, sandy nests.
Male studs are often most at risk
The seduction routines of many species make them particularly vulnerable to overfishing. Some males will swim higher-up in the water column, displaying their suave bodies for the females to observe, while aggressively chasing away other males. In their amped-up state, these males are more likely to bump into fishing gear located mid-water, and to take the bait. The biggest, most colorful males are often the most attractive to females and to the aquarium trade, which selectively captures these flashier individuals.
Targeted fishing skews sex ratios and disrupts established hierarchies of dominance that female fish rely on to select their mates. Imagine living in a small town with more girls than boys, and all the smart, attractive guys have taken off for the big city. These female fish are left with slim pickings, and while they eventually settle for nearby mates, they may take longer to reproduce and may reproduce less than they would given a more attractive dating pool.
As Dr. Yvonne Sadovy of the University of Hong Kong notes:
There are many complex behaviours associated with mating in many fish species and heavy fishing can directly affect mating or indirectly affect reproduction if numbers get too low (called depensatoin) - these effects are not typically considered in conventional fishery management measures.
Sex-change Gone Awry
Many of our favorite seafood selections, including shrimp, oysters, and several fish, are sex changers. They start life as a female or a male, and then transition to the opposite sex at a certain point. When to switch depends on the presence (and size) of their neighbors. How many other males are around? Are you likely to win over a harem of females given your current stature? Or is it better to grow a bit bigger first? Alternatively, for oysters that change from male to female, an individual needs to be large and healthy enough to start producing energy-rich eggs.
The ability to change sex is a tried and tested strategy for boosting reproduction. But a flexible sexual state makes these species highly susceptible to “unnatural” sex-change.
While selective fishing can alter sex ratios in these populations, it’s not the only way we sway sex change in the sea. Introduction of synthetic hormones and pollutants from our drains and factories disrupts sexual development in all kinds of sea creatures. Scientists have discovered females with male parts, and males with female parts in coastal species of crustaceans such as crabs and amphipods, and in fish. In one incidence, female snails began growing penises so large that the penises blocked their reproductive tracts, preventing the release of eggs and causing the female snails to explode.
The resulting crash in snail populations led to declines in fish and other species that depended on the snail for food. The culprit: a toxic chemical that was ubiquitous in the paint used to coat the bottom of boats. Known as TBT, it has since been banned and snail populations are on the rise.
Supporting Sex-Friendly Seafood
Like the global ban on TBT, there are solutions for each of these threats to successful sex in the sea.
Sustainable fisheries have rules and enforcement in place that protect spawning aggregations. They close fishing for that species during certain times of year or forbid fishing on the spawning grounds. Populations in regulated areas have indeed shown signs of recovery. Grassroots campaigns, like the local Fiji residents who gave up eating grouper during spawning season, can also have a major impact.
If you’re traveling to the tropics this winter, be sure to check on the local fish fare. Many species of grouper spawn from December to February in the Caribbean and shouldn’t be caught—or served—during this time.
Generally speaking, species that are lower on the food chain make for more sex-friendly seafood options. Choose fish like herring and mackerel. These species grow fast, mature quickly, and tend to spawn over several weeks of the year. Their habits and growing patterns allow them to withstand a good deal of fishing pressure—but not an infinite amount.
Many such “forage fish” have been largely unmanaged. Declines in small fish populations, and the resulting impacts on species that depend on these small fish for food such as seabirds and sea lions, has called attention to the need for increased regulation.
And the government is responding. In April 2016, NOAA passed a final ruling that includes small fish in the overall management plans for west coast commercial fisheries in the USA. More work must be done to ensure that we manage the oceans’ smallest fish and their larger cousins. But let’s just say things are moving in a more productive direction.
A Guide to Sex-Friendly Seafood Selection
This World Ocean’s Day, we can support—rather than thwart—sexual success of our favorite seafood. Here’s a quick Guide to Sex-Friendly Seafood Selection:
1. Avoid buying species caught from spawning aggregations or during their reproductive season (well-managed forage fish can be an exception). Most sustainable seafood guides, like this one by Seafood Watch and certifications such as The Marine Stewardship Council, include consideration of reproductive strategies in their rankings. They’re good sources for finding sex-friendly options.
2. Look for shellfish and seaweeds—they spawn so profusely that they can withstand a bit of fishing pressure.
3. Know your fish: support Community Supported Fisheries (CSFs) where you can talk with your local fisher and ensure the local catch is sex-friendly. See LocalCatch.org to find a CSF near you.
4. Reduce pollutants. Choose environmentally-friendly household cleaners and personal care products, and support legislation that aims to reduce introduction of chemicals and plastics into the ocean. Check out Marinebio.org for more on ocean waste and links to support policies reducing ocean pollution.
Instead of viewing oysters as aphrodisiacs for us, let’s consider what we can do to boost the sex lives of sea life. Buying seafood that has been harvested in a manner that supports successful sex in the sea is a great place to start (and oysters are a fantastic option!) Follow #sexfriendlyseafood for more information and to join a Twitter Chat with seafood sexperts at 12pm PT for a lively (and salty) discussion.