How Long Can Fish Survive out of the Water?

How Long Can Fish Survive out of the Water?

Everybody who has ever caught a fish has taken a fish out of the water. While taking a long time to remove a stubborn hook or to get the right pose for a picture, most of you have probably wondered, “how long can this fish safely stay out of the water?” Well, this is my area of research expertise: fish out of water! Some fish can survive for a few minutes out of water, some for a few hours, and some for even a few months! This mostly depends on the species of fish, the habitat/environment, and how long you fight the fish.

 A surprising number of fish that you may catch around the world actually have air-breathing organs or can breathe air through their skin! This includes tarpon, arapaima, walking catfishes, snakeheads, eels, bowfin, lungfishes, gars, and more! Some of these fish are limited in their air-breathing, like tarpon which will gulp air from the surface during long fights to get extra oxygen and bursts of energy. Others like snakeheads and walking catfish have well-developed air-breathing organs that allow them to survive many hours out of water.

Many killifish can breathe air through their skin quite efficiently, and are tolerant of low-oxygen conditions (hypoxia), which is why they survive quite well in bait buckets when other baitfish (minnows, shad, etc.) do not. Furthermore, the most extreme of killifish, like the mangrove rivulus, can survive out of water for over a month at a time (Bressman et al., 2018; Taylor et al., 2007)!

A large American eel I caught comfortably slithers around on the grass due to its air-breathing capabilities.

If a fish can’t breathe air, though, it doesn’t necessarily mean it’ll die right away out of the water. Your usual catfish species (channel, blue, etc.) are particularly tolerant of low-oxygen conditions, and I have seen them alive out of the water for multiple hours! However, some fish are less tolerant of being out of the water than others. In particular, trout fair particularly poorly when out of the water for even a few minutes.

Fish with slow metabolisms and those that live in cold water can usually survive a good bit of time as long as it’s cool; metabolic rates and oxygen demand are generally lower for fish in cold water, so they can survive without breathing longer. For instance, I caught pike while ice fishing and immediately put it on ice. When I opened my cooler a few hours later, it was still movie! Conversely, many fish caught in very warm water require a lot more oxygen and likely will not survive as long out of the water.

Most importantly, the longer you fight a fish, the more oxygen it’ll need to recover, so the quicker it needs to go back in the water. Just imagine running a marathon and then immediately trying to hold your breath underwater – you won’t last long. After a long fight with a fish, it is important to get it back in the water ASAP so that it can “catch its breath” and recover. Sometimes, the fish will need some help if it’s very tired, and you will need to perform fish CPR – moving water over the fish’s gills or moving the fish through water to help increase its oxygen uptake, so that it can safely recover.

What about the average, non-air-breathing fish that didn’t spend a long time fighting on a moderate-temperature day? Fish like bass, perch, and drum that don’t have any air-breathing adaptions are usually fine being out of the water for a few minutes out of the water, but it’s best to return fish to water as soon as possible to reduce their stress! If it takes several minutes to get a stubborn hook out, these fish should still be fine if you release them, but keep an eye on them when you put them back in the water. If they are struggling, you may need to perform fish CPR on them until they can swim away on their own.

Interested in learning more about fish out of water and amphibious fishes? Check out my current project that I am crowdfunding on the terrestrial orientation and behavior of invasive walking catfish: https://experiment.com/projects/how-do-amphibious-fishes-find-their-way-around-on-land, or feel free to reach out to me on social media to ask a

IG: noahwithfish

Twitter: noahwithfish

Noah Bressman is a PhD candidate studying fish biology, behavior, and biomechanics at Wake Forest University. Below is Noah with a Blue Catfish (Ictalurus furcatus), caught on cut bait while night fishing in the Pee Dee River in NC.

References

Bressman, N. R., Simms, M., Perlman, B. M., & Ashley‐Ross, M. A. (2018). Where do fish go when stranded on land? Terrestrial orientation of the mangrove rivulus Kryptolebias marmoratusJournal of Fish Biology, doi: 10.1111/jfb.13802.

Taylor, D. S., Turner, B. J., Davis, W. P., & Chapman, B. B. (2007). A novel terrestrial fish habitat inside emergent logs. The American Naturalist171(2), 263-266.

I’ll Have a Side Salad with My Squid: A Shark Species that Eats and Digests Grass!

I’ll Have a Side Salad with My Squid: A Shark Species that Eats and Digests Grass!

Samantha Leigh taking a selfie with a bonnethead shark in a seagrass meadow.

Sharks eat meat. That’s kind of the big thing about being a shark. Whether you’re a 20 ft. great white shark that bites seals in half, a 40 ft. whale shark that filters microscopic zooplankton out of the water, or a 4 ft. leopard shark that sucks worms out of holes, you’re a carnivore.

However, many anglers who have caught and filleted bonnethead sharks (Sphryna tiburo) have noticed that their stomachs are often filled with seagrass. Since these sharks often feed on shrimps and crabs living in seagrass meadows, people usually assume they accidentally swallowed some grass with a crunchy crustacean. According to new research by Samantha Leigh, a PhD candidate at UC Irvine studying digestion in fishes, their side salads may actually be the main course!

In her newest study, Leigh fed bonnethead sharks a diet consisting of 90% seagrass wrapped around 10% squid (to give the grass scent) for three weeks. Not only did these sharks survive, but they thrived, gaining weight on their mostly herbivorous diet (Leigh et al., 2018). Now, it could be possible the squid was enough for them to survive, but Leigh and her team thought of that. They labelled the seagrass with a tracer (13C), and found that seagrass was actually digested and became part of the sharks’ bodies!

Plants are harder to digest than meat, though. That’s why many herbivores have very long intestines, to allow more surface area for digestion and nutrient absorption. Additionally, herbivores like cows and sheep have multiple “stomachs” and special bacteria to help them digest plants. When it comes to bonnetheads, their digestive tracts look just like any other shark’s. Leigh hypothesizes that while they may not have extra stomachs, they likely have specialized gut bacteria that aid in digesting plants.

A seagrass meadow from a bonnethead’s perspective (but from Leigh’s camera).

So, these sharks are omnivorous, sometimes eating plants, but why is that important? Seagrass meadows are very important ecosystems because they filter toxins, produce oxygen, and provide a safe nursery habitat for juveniles of many species.

However, seagrass meadows are on the decline for a variety of reasons, including disease epidemics and human activities. Many people are trying to figure out how to conserve seagrass meadows, but none have factored in that millions of bonnethead sharks are potentially eating lots of seagrass. This is important information when considering ecological models and management actions because the bonnetheads may have a more important role in seagrass meadow ecosystems than previously thought.

Furthermore, if you are trying to catch bonnetheads, you may be able to catch them using plants as bait! While right now the only plant they are known to eat is seagrass, it may be worth keeping cans of corn in your boat to fish for them like carp if you ever run out of fresh bait (if you do catch one on corn, please let me know right away). At the very least, you may be able to make your bait last longer by putting smaller pieces of bait on the hook with some seagrass, or even just rubbing some squid on some grass to give it some scent!

IG: noahwithfish Twitter: noahwithfish

Noah Bressman is a PhD candidate studying fish biology, behavior, and biomechanics at Wake Forest University. Below is Noah with a Common Carp (Cyprinus carpio), caught on canned corn while night fishing in small pond in Thornwood, NY.

References

Leigh, S. C., Papastamatiou, Y. P., & German, D. P. (2018). Seagrass digestion by a notorious ‘carnivore’. Proc. R. Soc. B285(1886), 20181583.

 

Microfishing: Catching More by Catching Less

When I was fishing a species tournament with Ronnie Green this past winter near Tampa, it wasn’t the unimpressive 14” redfish or the 20” Spanish mackerel that won the tournament for us; we won by targeting the smaller species, like squirrelfish, pinfish, and puffers, that the other teams weren’t targeting.

Since there are more species of small fish in the ocean than big fish, our strategy helped us win. In general, as G. Evelyn Hutchinson (1959) described, there’s a greater diversity of smaller species than large ones because there are more niches to occupy and a wider range of diets and habitats for them to exploit. However, most fishermen tend to target the relatively few large species because a 4’ snook is more impressive and puts up a larger fight than a 4” creek chub.

Ronnie with a very unimpressive Hardhead Catfish (Ariopsis felis), that helped us win the species tournament! It’s not the size or number of fish that help you win species tournaments, but the number of species that you catch.

Not microfishers, though. Microfishers are people who use extra light tackle and small hooks to target small fish, often in small bodies of water like tiny creeks, tide pools, and puddles. Some microfishers (like myself) target these smaller fishes to add to our lifetime list of species (I am up to 322!). We are called lifers. 

However, most microfishers aren’t lifers and don’t always target micros. Often they just use small hooks when going for trout or reef fish in the hopes of catching a great number of fishes. This may risk a straightened hook on the biggest of fish, but allows you to catch those smaller fish that keep nibbling away your bait. When the bite for bigger fish slows down, it’s nice to at least catch small fish rather than no fish. 

Microfishing is also about the challenge of catching the smallest fish possible in the smallest body of water on a hook and line, often in a scenic area. Sure, anybody can catch a big shark at the beach by surfcasting with some cut bait on steel leader. It takes real skill, determination, patience, and powerful thighs to hike to a remote mountain stream and catch rare, beautiful color morphs of small trout and darters on a size 28 hook.

Many microfishers fish remote places that few people have ever been, let alone fished. Recently, I caught a variety of micros while fly fishing a gorgeous North Carolina mountain stream, where I did not see a single person the entire day. I wasn’t catching the biggest fish, but it was an extremely peaceful and relaxing experience.

Noah with al Rock Bass (Ambloplites rupestris) caught in a remote NC mountain stream on a streamer. It’s a refreshing change of pace to have a solitary day of fishing, compared to the lakes filled with tons of bass boats.

Lately, when I don’t have time to load my kayak onto my car and drive to a big lake, I simply put a tiny nymph on my 3 wt fly rod and go for minnows and darters in a nearby stream. It’s just nice to fish even for a few minutes on a busy day, hoping to catch any fish and add some new tiny species to my list.

If you want to catch some new species, which are often extremely beautiful, like many small coral reef fishes (damselfishes, angelfishes, butterflyfishes) and some small creek fishes (chubs and darters), you should give microfishing a shot! It is also a great way to explore new bodies of water, give your fishing skills a challenge, and to figure out what those little fish in the creek by the park are!

Noah Bressman is a PhD candidate studying fish biology, behavior, and biomechanics at Wake Forest University. Below is Noah with a Bluehead Chub (Nocomis leptocephalus), caught on small nymph while fly fishing in 3’ wide creek in South Mountain State Park, NC.

References

Hutchinson, G. E. (1959). Homage to Santa Rosalia or why are there so many kinds of animals?. The American Naturalist93(870), 145-159.

The Ones That Get Away: How Predatory Fish Pursue Evasive Prey

The Ones That Get Away: How Predatory Fish Pursue Evasive Prey

A snook (Centropomus undecimalis) pursuing a crankbait. Photo by Jason Arnold.

Whether it’s stripping streamers for trout, trolling plugs for mahi mahi, or reeling in a spinnerbait for bass, we have all had fish follow our lures all the way in. We hold our breath, waiting for the strike… but it never comes, and the fish turns away. Furthermore, I’m sure you’ve had a fish strike your bait, but miss (more often than not, if you ask me). Why do predatory fish sometimes miss and why don’t they strike sometimes when pursuing prey? I asked Dr. Matt McHenry, a biology professor at the University of California, Irvine, these same questions after his presentation on “How fish predators pursue evasive prey” at the Society for Integrative and Comparative Biology’s Annual conference a few weeks ago.

To understand how a fish pursues lures, we first have to understand how they pursue and capture evasive prey. I discussed how fish capture their prey in a previous post, so I will focus on the pursuit here. On land, predators mostly have to pursue prey in two-dimensions, which can make chasing after prey easier since most prey has to stay on the ground and cannot go down or up.

Fish, on the other hand, live in a highly three-dimensional (3D) world, and can move in any direction, which makes pursuing prey a bit more challenging. Despite this fascinating complication to pursuing prey in an aquatic environment, Dr. McHenry was shocked to find out that very little research exists in this field. In order to find comparisons for fish hunting in water, he turned to examples from another 3D medium: air.

Many aerial predators, like dragonflies and birds of prey, use a pursuit strategy known as parallel navigation (PN). According to Dr. McHenry, PN requires predators to sense the heading and speed of the prey relative to the predator, so that they can intercept the prey. However, it doesn’t appear as though fish use PN, as that strategy “may be difficult for vision underwater, especially when the water is murky and the prey offers a poor contrast to its background.”

Instead, as Dr. McHenry explains, fish use a deviated pursuit (DP) strategy, which only requires predators to sense the position of the prey and the direction it’s moving. Think of DP like chasing a friend in a game of tag, while PN is like a safety trying to predict where a running back with the ball is going, to make the most of his one chance at tackling him. DP is likely the most robust strategy for fish in aquatic environments, where predators try chase and out-swim evasive prey before they can evade, like the lucky mummichog below.

A Bluefish (Pomatomus saltatrix) pursues and misses a Mummichog (Fundulus heteroclitus). Video by Dr. Matt McHenry.

So, you have a fish following your lure. What can you do to improve the odds of the fish continuing to pursue your lure and for it to make a successful strike? If you slow down or stop your lure and keep it at the same position, that would make it easiest for the predator to intercept it, says Dr. McHenry, but that doesn’t look natural and may not entice a wary predator to strike.

If you keep the retrieval at a constant speed, that would be the next easiest way for the fish to intercept your lure, but again, this may not look natural to the fish. It’s a trade-off: you want your lure to seem like an evasive prey to entice a strike, but you don’t want it to be so evasive that the fish misses your lure. Personally, when a fish follows my bait, I slow the retrieve, give a couple of sudden twitches, and then a half-second pause after the last twitch, at which point, BAM!

IG: noahwithfish

Twitter: noahwithfish

Noah Bressman is a PhD candidate studying fish biology, behavior, and biomechanics at Wake Forest University. Below is a young Noah with a Bluefish (Pomatomus saltatrix), caught on chunk bait in the Long Island Sound, NY.


For more information on fish predator-prey interactions, check out these recent research articles from the McHenry lab:

Nair, A., Changsing, K., Stewart, W.J. & McHenry, M.J. (2017) Fish prey change strategy with the direction of a threat. Proc. Roy. Soc. B 20170393. doi:10.1098/rspb.2017.0393. 

Nair, A., Nguyen, C. & McHenry M.J. (2017) A faster escape does not enhance survival in zebrafish larvae. Proc. Roy Soc. B 20170359. doi:10.1098/rspb.2017.0359.

Soto, A., Stewart, W.J. & McHenry, M.J. (2015) When optimal strategy matters to prey fish. Integrative and Comparative Biology. doi:10.1093/icb/icv027

Stewart, W.J., Nair, A., Jiang, H. & McHenry, M.J. (2014) Prey fish escape by sensing the bow wave of a predator. Journal of Experimental Biology 217: 4328-4336. doi:10.1242/jeb.111773.

What’s the Best Way to Hold a Fish?

What’s the Best Way to Hold a Fish?

You’ve a caught a nice fish and have it close to the boat or the shore, and you’re trying to figure out the best way to hold the fish to get the hook out and take a photo. We’ve all been there (and if not, you’re probably at the wrong blog…). Should you grab it by the lip? By the gill cover? By the tail? One hand or two? Gaff? Net? I’m here to set the record straight on the best way to land and handle a fish for the fish’s health and the best way to photograph with a fish to show off your catch like a pro!

When it comes to landing a fish, a lot can go wrong. You can miss with the net, scaring the fish onto a run through the boat prop. You may try to gaff a fish through the mouth, missing and hitting it through the skull. You can also lift a fish straight out of the water by the line, and have the line snap while you are so close to bringing the 5 lb. rainbow trout onto the pier (sorry Trent).

According to fisheries scientists John Tiedemann and Dr. Andy Danylchuk (2012), the safest way to land a fish is to not actually land it; keep the fish in the water and grab it with your hands or a net. Many fish can be dehooked and photographed easily while in the water, like the tarpon below. This keeps the fish safe by surrounding it by water, and it prevents it from thrashing on the boat/ground which can cause damage to you, the fish, and your stuff. If you must bring it onto the boat or on the shore, a net is the best option, as it’ll cause the fish the least harm. Gaffing a fish is fine for a fish that you plan on keeping, but is not recommended for catch and release as it can mortally wound a fish.

Noah and Capt. Colt Harrison with a monster tarpon. It was dehooked, photographed, and released without leaving the water.

Bringing a fish onto the boat safely is also important for your photos as a vibrant, colorful, healthy looking fish makes for the best photos. Now, what’s the best way to hold it to make it look as big as possible without hurting the fish? A recent study by Skaggs et al. (2017) showed that in terms of long-term survival, there really is not much of a difference to largemouth bass if you hold them vertically by the lip with one hand/lip gripper or if you hold them horizontally with an extra hand to support the belly.

Bigger fish have more weight to be pulled down on by gravity, though, so larger species like striped bass should be held horizontal to avoid damaging their jaw or internal organs. Fish with teeth shouldn’t be lipped at all (duh), but you can still support their belly with one hand and their tail with another. Holding fish by gill covers should be avoided as this can damage their gills. Many also fish have sharp gill covers, like snook, and can badly cut your hand if you hold them like that.

Noah with a common snook (Centropomus undecimalis), supporting its belly at arm’s length, with a slight bend in the elbow while facing the sun. This makes this 5 five pounder look like a 10 pounder!

Fish do revive more quickly when you hold them horizontally for photos and dehooking (Skaggs et al., 2017), though. So, while lipping fish my not harm them in the long-run if you revive them properly (see blog post on fish CPR), it is best for them if you support their belly with a hand as well. Supporting the belly also makes for a great picture, as it bulges the belly out, making the fish look fatter! For best photos, you should also hold the fish out almost at arm’s length, to make the fish look as big as possible. However, you’ll want a slight bend in your elbows so it doesn’t look like you’re doing that. For best lighting, face the sun, preferably with sunglasses. Then, take the photo as quickly as possible, as a fish’s colors will fade the longer it is out of the water. Now, send in your best fish pics to @AFishingStoryTV!

Noah Bressman is a PhD candidate studying fish biology, behavior, and biomechanics at Wake Forest University. Below is Noah with an Atlantic Salmon (Salmo salar), caught on a blue and silver Kastmaster spoon at Seneca Lake, NY. Note the hand on the bulging belly makes the fish look fatter, but the hand in front of the tail obscures the tail. For the best photos, you should hold the tail from behind.

References

Skaggs, J., Quintana, Y., Shaw, S. L., Allen, M. S., Trippel, N. A., & Matthews, M. (2017). Effects of common angler handling techniques on Florida Largemouth Bass behavior, feeding, and survival. North American Journal of Fisheries Management37(2), 263-270.

Tiedemann, J. & Danylchuk, A. (2012). Assessing Impacts of Catch and Release Practices on Striped Bass (Morone saxatilis) Implications for Conservation and Management. https://www.monmouth.edu/uci/documents/2018/10/best-practices-striped-bass-catch-and-release-report.pdf/