Reading Fish Behavior: Identifying What The Fish is Going to Do
The short version is that every fish species acts differently, and individual fish within a species will adapt as well. With experience, there are strategies we can learn that improve our ability to read fish behavior and get closer to all fish species. There are also broad categories for types of fish that can help determine how a given species may act. There are other factors that may impact how fish may act. For example, frequency the fish is hunted in a given area, or time of year are both factors that can influence how a fish can be expected to act. Ultimately, your experiences will dictate how you interact with certain species of fish.
Reef Fish Behavior
Reef fish are generally fish found towards the bottom of structure. Grouper and Snapper are common examples of reef fish within the United States. Sea Trout and Job Fish are example in Australia and other parts of the Pacific. No matter where you are in the world there are always a few species that are easy (or easier) to hunt. We will focus on species that tend to be harder to hunt.
Large reef fish tend to be weary of new arrivals to their environment. There are two broad actions you can expect most reef fish to do. They will either swim away, or be curious. If they are curious the best thing you can do is be still on the bottom and try and wait them out. Use a rock to hide behind for a better opportunity. If they are swimming away you have two main options. You can either try and chase them down, or you can call your dive and try and approach the fish from another direction. For a more in depth breakdown of the best method to do this check out the Hunting Techniques blog post and skip to the “Cone of Death” section.
Pelagic Fish Behavior
Pelagic species can be a bit harder to read in the water. Because they are more rarely seen in a day of diving it is easy to forget about hunting techniques and to just try and run them. This usually results in the fish getting spooked and swimming away faster than you have any hope in catching up. The best thing to do with most blue water species, like Wahoo, is to take a calm breath and try to create an intersecting path with the fish. Body language is everything when spearfishing. In simple terms you want to be the sea turtle instead of the shark. Not to sound too corny, but you almost have to lie to yourself and think that you don’t want to kill the fish. If you believe it the fish may believe it, and that can help you close the distance.
There are highly migratory species that tend to congregate on reefs as they move through an area. Mackerel are a common species that can be found on normal reef structure during certain times of year. These species tend to turn into targets of opportunity. Some of these species can come through and you may be lucky to see them ever again, so you may have to take advantage of them coming through quickly. Other species may simply do large loops on structure. Cobia are an excellent example on some shipwrecks. It is common for cobia to do large circles outside a bait ball on a shipwreck. When they do this you can just try and make an intersecting path with them and wet within range of the fish to close the deal.
There are countless factors that impact how fish behave. Below is a description of a few common factors and how they can impact fish behavior and hunting technique.
As we mentioned earlier, there are several factors that can impact how a fish can behave. One of the biggest factors that can change behavior is a fish spawn. Spawns are different for most species of fish. Many fish species have evolved to have mass spawns to improve the likelihood of successful breeding. That means that during certain times of years there tend to be large aggregations of a given fish species in one location and they tend to be focused on breeding rather than avoiding predation. This can afford a diver the opportunity to hunt large fish of a given species where a fish may not be as focused on avoiding the diver. There is the moral issue of knowing you are taking advantage of the fish, but that comes down to the individual diver and what they are comfortable with. Other species tend to show up around other spawns as well because the spawn acts as chum in the water.
Moon phase is a common consideration for fish behavior. It often dictates when some species spawn. The moon also impacts tides and currents. Tides and currents are an under appreciated element of fish behavior. Fish tend to be more active the stronger the current and the more water that is moving. Fish tend to move up current because of the nutrients that are moving into their area. Strong currents defiantly can make for challenging dive conditions, but they do usually afford more opportunities for shooting fish.
A thermocline is a dramatic difference in water temperature. This can impact how bait fish and other species behave. Often times fish will sit just above or just below the thermocline. This means you can plan to hunt a species by identifying how they are going to act on that day. Typically the thermoclines get colder as you get deeper, so you may be able to identify if the given species prefers warmer or colder water and target them in the window they prefer. There can also be dramatic differences in visibility between two thermoclines. Water temperature is defiantly a driving factor in how certain species behave.