Freshwater Fishes: a big observation gap

Nature Talk
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Oh, yes – memories of California. Where I was about to try to swim the very short distance across the Napa River, and a bystander warned me not to. I came away wondering why the people of Napa didn’t care that their river was so nasty.

Here in Greenville, this is the second season that I have been one of the Swim Guide water sampling volunteers. Our Riverkeepers stay on top of water quality, and when a given stream fails Swim Guide testing, they investigate to find out why. Most of our waterways pass most of the time.

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If the fish has moved a reasonable amount after being released, it can be considered wild. If it was released in a pond or other smaller body of water where it couldn’t move away from the stocking site, I’d consider it captive in perpetuity.

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By remaining almost completely still in the limpid water of an upland lake I was able to nab a few photos of the 2-3 species of fish that came to feast on my dead skin flakes. See this observation for example. Unfortunately none of my photos provide a clean lateral view of the fish.

After a 1-2 hour wait, I managed to catch this little stickleback out of a ditch using a bottle trap. I would say unless an observer is specifically motivated to catch and/or photograph fish, they are unlikely to get a crisp photograph out of a chance encounter with one or many fish. On the contrary, it is relatively easy for the same observer to get an identifiable photograph of a bird that they cross paths with for only a few seconds.

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One word:

Crocodiles.

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Alligators were my concern in Florida. I did a lot of looking over my shoulder while snorkeling there.

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I’m an amateur scuba diver and a generalist as far as observations go, but I think I’m amassing marine fish observations much more quickly than freshwater ones, both in species and in observation counts. I’d love to observe more freshwater fish, but it does feel challenging! Personally, a couple of factors stand out to me.

If I’m scuba diving, I need deep-ish and relatively open water; streams and ponds that are less than two meters deep, or boggy lakes full of logs and dense marginal vegetation, don’t feel like apt dive sites even if there are plenty of fish and other cool animals. I also need a dive buddy, and for whatever reason (and there are many reasons), a lot of the scuba divers I’ve met don’t seem interested in freshwater environments. Sometimes they’re interested in lake wrecks or challenging drift dives in rivers, but the ecology-focused divers seem to think the ocean is just way more interesting. I still need to find dive buddies who are excited for freshwater diving.

Setting aside scuba, I’ve snorkelled in some lakes for observations, and an environmental difference I’ve noticed is that there seems to be more animal life congregating on static surfaces in the ocean than in freshwater. Rock walls in the ocean are covered in inverts, and small fish will rest on the walls or substrate while larger fish will patrol the area; they will move to avoid me, but often they only really scare out of photo range if I make sudden movements very close to them. In freshwater environments by contrast, the fish I see while snorkelling are often moving quickly through the water column, and they feel no compunctions about just zipping away the moment I make any movement, so it’s very hard to get photos. For example, I saw tons of these fish recently, but this was about the best I could get; this blurry photo was more average. Compare that to this gorgeous photo I got almost by accident while scuba diving along a pier; I didn’t even notice the fish until I was right next to it, and it stayed almost perfectly still.

The substrate in the lakes where I’ve snorkelled is also much less solid and busy; I’ve seen frogs and newts just dive straight into the muck like it’s fog. There’s not really a solid “floor” to support an obvious benthic community of inverts to observe while I’m there. In the ocean, there’s lots to observe besides fish - so many crustaceans, crinoids, cnidarians, etc. - so it feels overall very rewarding as a generalist observer.

I’ve also tried dip-netting in freshwater environments, which has been fun, but hasn’t yielded any fish. I think part of the issue is that I don’t have great technique yet, but I also don’t think dip netting is great for finding fish generally? I’m mostly looking for and finding arthropods when I do it.

I’m sort of left feeling like if I want to invest in really upping my freshwater fish observations, I should acquire gear for trapping, netting, or fishing; but this feels like a distinct set of skills and a distinct set of equipment (and expenses!) that I don’t feel I have the bandwidth to invest in yet.

The one remaining factor that’s more personal than structural is access; there are certainly large, open freshwater lakes and rivers near me, but I don’t have a car, so the only freshwater I have access to are places I can convince someone to drive me, or places I can get to with transit… which invariably means transiting to one of a few suburban trailheads, then hiking a few hours to get to a lake, and there are only a small handful of swimmable lakes actually accessible to me this way. Many (most?) urban and suburban lakes and rivers around here are flagged as too polluted for safe swimming, or are municipal water reservoirs where swimming is forbidden. Compare this to the ocean - I live in a coastal city, and there are many, many shoreline areas that are accessible via transit (and I have dive buddies who are happy to drive and dive with me in the ocean!), and most of them have quite clean water according to quality tests the city conducts.

So I end up visiting swimmable freshwater bodies maybe 1-2 times a year because of the scheduling hurdle - and I do want to! I enjoy my time observing in lakes. I tend to avoid rivers because, well, they feel scarier than lakes to me, what with the faster-flowing water and the fact that they are often less frequented and their hazards less surveyed than small lakes.

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48

As someone who both observes and IDs North American freshwater fishes, I think there’s multiple parts to this, and I agree with a lot of the previous replies here.

Most iNat observations are going to be people going out for a walk, or looking out their backyard window, and stopping to take pictures of birds and plants they can find. I know that I’ve posted mushrooms and birds I’ve seen on my way to campus, or skunks and groundhogs living under my porch, and there wouldn’t be any way to observe fish in my day-to-day life except when I go out on weekends.

I think most people will almost always observe freshwater fish through angling (another very common method is dead fish washed up on shore). It’s the most accessible to people, because it’s a common pastime many people grow up with. Anglers don’t always need to get in the water to catch fish, removing concerns about pollution exposure, clarity, and current. Gear is easily purchasable from local stores, and gas stations sell fishing bait. As someone who mostly observes fish through angling, most days I’d rather not go through the trouble of getting wet, except if it’s a hot summer day.

As a result of the angling bias, I think gamefish will always be a large chunk of fish observations-- but this seems to be evening out. I see more and more micro-anglers and lifelisters targeting shiners, darters, and madtoms with tanago hooks; I see people dipnetting or seining for these fish; and I also know of several accounts employed by state agencies that post their fish sampling trips, which provides a great look at both game and nongame species. Due to the actions of some very dedicated users, there is an increasing amount of shiners, darters, and other overlooked fish too small to catch via conventional angling.

For what it’s worth, the North American freshwater fish observations we do have can be quite high quality depending on the area. Minnesota’s freshwater fishes cover almost every species seen in the state (including rare fish such as Plains Topminnow or Topeka Shiner), and nearly 97% of the total observations are Research Grade.

I think coral-reef diving is so biased towards observations because: 1. it’s a popular activity 2. There are several high-powered observers who upload their tens of thousands of dive photos to the site 3. Coral reef diving spots tend to have clear water, shallow depth, and calmer currents 4. Coral reefs have a high species diversity, so not only species-rich (high numbers) but also highly abundant fish, so you can observe many more species more quickly than most freshwater areas in the U.S.

Most freshwater is not going to be clear (most warmer rivers wider than 20ft have little or no visibility), and the clearest freshwater is going to be relatively isolated small streams or lakes. In inland urban environments, most people’s exposure to water will be rivers passing through town or small neighborhood ponds choked with algae. Many rivers, even some smaller ones, will have dangerous current that can make underwater observation inadvisable or impossible, regardless of clarity.

I’ve noticed that observing most fish from the surface produces un-IDable photos (there are so many “Leuciscidae” or “Ray-finned Fishes” observations) due to glare, distortion, and top-down being bad for fish ID. Even underwater photography is not perfect; I’ve seen too many observations of underwater fish that I have to leave at family level, because for most minnows observing them in hand just makes ID much easier.

The bulk of freshwater fish biodiversity is in the tropics (especially the Neotropics), where warm water temperatures allow silt to dissolve more readily and make observing fish underwater impossible in many places. Additionally, much of this diversity is going to be within remote, dense jungle with limited towns or cities nearby. Most observations are going to be near population centers because that’s where the most people are going to spend most of their time. It doesn’t help that it seems iNat’s data is mostly biased towards people living in the U.S. and Europe, and I hope we can recruit more observers from underrepresented places to fill in these gaps.

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The best way to sample freshwater fish is pulling a seine net, but there are usually two obstacles. You need at least 3 people to operate a seine well (two on each end to keep the lead line down and pull upstream and one “kicker” to drive to fish into it). You remove one part and your net is fixed on one end or the fish get under the lead line, and remove the kicker and the fish simple run upstream or around the net. I have tried using a seine by myself and the results are beyond pathetic. Maybe a smaller net or a different type of net works better?

Fish that live in deeper unwadeable rivers and creeks are a different challenge. You can only fish for larger species and sometimes these rivers are dangerous (flow or gators) or turbid/blackwater. VERY few people have trawl type nets.

The worst gaps on iNat are the smaller and deeper fishes and inverts. The vast majority of SCUBA divers are staying shallow and focusing on the charismatic species. Hence my tangent to using alternate sources to get the images to at least get each species represented in some form on iNat.

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In my experience, electrofishing (backpack for small streams, boat boomshocking for large, inaccessible rivers) is the best way to sample freshwater fishes, since everything in the immediate area rises to the surface. However, I agree seining is second place (despite the problems you’ve mentioned). Unfortunately, electrofishing is really only accessible if you’re a researcher or with a state agency, so most people will probably be netting or angling.

I agree with there also being a huge gap with deepwater marine fishes inaccessible to divers, and I think the only way to really add to that would be to get more observers that are working on deep-sea trawlers (researchers, deep-sea fishermen, etc.). Trawlers get a large abundance of catch, done repeatedly over large areas, where one could easily get multiple observations of a species over time.

I think the images from deepwater ROVs would have to be up to the operators themselves, because presumably they not only have the copyright but also the exact location needed by iNat. Having people uploading those who don’t have that information or own the images seems like it would lead to a flood of poorly localized observations to me, and might not provide much more insight than the current state of no information.

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I’ve tried cast netting and gotten nowhere with it; I tangle the hell out of the net and get nothing. I’ve thought about seining but safety and manpower are both an issue. My kids enjoy dipnetting weird stuff for me to see but that’s about it

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sigh
The remains of a 12 year old child have just been found at a creek where she disappeared earlier this week, a crocodile is suspected.

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Oh, dear, that’s really sad.

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I often ask to photograph a fish someone catches when I’m nearby, but asking incoming fishing boats is genius! Around here, fish you can keep would come from the bay or open sea. I have to see how I could manage that.

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For folks considering taking observations from incoming fishing boats, keep in mind that observations represent the observer’s experiences with nature. So observations made of catches from other folks’ boats, would be where the observer encountered the fish (dock or similar) and captive.

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Bit of a dumb question but to what extent does electrofishing harm fish? I always assumed it killed them? though I guess now that I think about it I wouldn’t be suprised if there was a spectrum from ‘temporary stunning’ to death (like that one ‘gate’ in the Great Lakes region).

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Not a “dumb question” at all! In most cases, the current used for electrofishing is low enough that injury and mortality is low. In my experience with it, most fish are stunned for a few seconds to a minute, then perk up again and swim away; if you’re not quick enough with the net you can definitely miss fish.

However, there is some mortality/injury associated with it; a quick search of the literature seems to show that risk depends on species, fish size, current level used, and other factors. In controlled studies, bleeding/spinal injury rates seem to be consistently below 10% and mortality below 20%. For further reading, see here and here

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This reflects my general experience when assisting with electrofishing as well. I will also note that humans (eg, me) can get quite a jolt if not adequately insulated but no long term issues…:)

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There’s a reason that shocker boats have a “dead man’s switch” foot pedal in the bow in case a dipnet operator falls overboard .

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If fish had rights comparable to those of humans, those figures would be unacceptably high.

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That seems a lot higher than what I’ve heard for backpack electro fishing but I’m not a fisheries biologist. Results can vary a lot however based on species, technique, and the sampling environment.