Spring Schoolies Part I: The Migration
Our striper population consists mainly from The Chesapeake Bay, Delaware River, and Hudson River ecosystems,
The striper migration has always fascinated me. Millions of fish from various and separate initial ecosystems coordinate themselves to swim up the coast to their preferred summer habitats without the luxury of Google Maps. How do they know where to go? What trigger's their migration? The stripers don't log into Facebook or check Yelp reviews to decide if Cape Cod Bay, Boston Harbor, or the Merrimack River is this year's hot spot. The annual journey ranging mostly from Maryland or New York to Canada is made possible through millions of years of biological evolution and natural events that trigger a cycle of patterns every season, year after year.
The majority of striped bass that we catch north of Boston comes from two separate main breeding grounds: the Chesapeake Bay and the Hudson River. In the past decade, more and more evidence has suggested that we may have more fish from the Hudson River ecosystem than previously thought. A few years ago, I had the pleasure to be in attendance for a seminar by Ben Gahagan from the MA DMF on the striped bass migration tagging study he and his team had been conducting. In a presentation chocked full of information, the most surprising thing I learned about the striper migration was the paths they had to take that would lead them to the Merrimack. In their study, the team found that as stripers approach the southern MA coastline, they can either shoot through the Cape Cod Canal or run the oceanfront around the elbow of the cape. Using acoustic tags and thoughtfully placed receivers, the team discovered that nearly 99% of the striped bass north of Boston took the path through the canal! Meanwhile, bass rounding the cape settle into the Boston Harbor and Mass Bay for the summer. Although I am not sure why that is the case, we are working with Ben to get him on a podcast soon to discuss his study in more detail!
Throughout the years, I have always kept close tabs on the early spring fishery and have played a game with myself to try to predict my first striper of the season. Collecting my data from my experiences, reading scholarly articles, and talking to old-timers, I have my thoughts on the spring striper migration that I would like to share. I want to stress that the following is more of a highly educated opinion than anything set in stone, but I believe that thinking of migrations in this manner has made me a better fisherman.
Ever wonder why, year after year, stripers seem to show up in numbers around the same time and, in most cases, in the same spots? From my couch research of various fisheries, it is apparent that there is an instinct or biological imprint that programs these fish to return annually to their homes. In the striped bass study mentioned earlier, Ben said that 90% of the tagged stripers detected for four years returned to the same coastal areas each year!
How do they instinctively know when to make their move? Out of all the theories, the one I subscribe to is the amount of available daylight seems to be the trigger of the northern (and southern) migrations of stripers. For this to make sense, we have to discuss some fish movement truths; Hear me out:
The dark lines over the blue water indicate the highways or contour lines. Notice they run un changed all the way up the coast. These ledges are how the fish guide themselves to their summer haunts.
Nearly every fish species get to where they are going by following "highways" or specific edges (depths) that run up and down the coast. For the tuna fisherman here, the "180 Line" is an example of a tuna hotspot that runs up and down the coast. Throughout the season, you will see a line of boats anchored up on various points on the 180 line from Maine down to New Jersey. The fishermen recognize the bluefin tuna use this contour line to make their migration up the coast and use it as a place to ambush tuna on their journey. When stripers begin their migration, they will follow a specific depth line as a road map to their destination. However, I believe there can be environmental triggers that can determine which contour line they will travel. As the days in the spring get longer, there is a trigger that puts these schools on the move regardless of weather, wind, etc... As the stripers down south expand outside their river systems, they find a contour line and continue to use it as a guide up the coast. Finding a comfortable depth for travel, in my opinion, has to do mainly with the amount of daily sunlight during their migration. If they are traveling deep, it may take a few days or a week later to move in on their inshore habitat to wreak havoc on the baitfish that await. There is some variability in the season for which "contour lines" the fish will follow. I believe that sunlight and wind patterns determine how far off the coast the predominant schools are moving. Think about it...
Fish do not have eyelids, which most people fail to consider while fishing to adapt their techniques for a given situation. The lack of eyelids is an overlooked aspect of fish biology is vital for two reasons. First, some genetic trigger (above my pay grade) signals to the fish that the seasons are changing, and it's time to move to put themselves in a more comfortable environment (water temp, bait, etc.). Second, the weather conditions DURING their migration can dictate which path they take to their resident waters. Fish want to be comfortable and are affected by bright, sunny skies: think of it as giving the fish headaches. To avoid the high sun and to make themselves comfortable, they have to move out into deeper, darker water. Thus, if the spring weather is prevalent with North or NW winds, the stripers will still show up in Ipswich Bay every year around the same day; however, they are out in deeper water, making them dormant harder to catch.
The vertical migration up the coast has shown that light levels signal season changes, but another critical factor is the moon phase. Stripers tend to be on the move during full and new moons throughout the season. It's another environmental change that can help you pattern fish throughout the summer. The high tides and stronger currents are triggers for fish that it's time to move on. Full moons that fall in the first two weeks of May tend to be the trigger to move the fish off the beach and into the rivers.
And lastly, the primary indicator that it's time for the fish to come in is water temperature. For the most part, people will start catching schoolie stripers in low numbers at 50 degrees (ocean temperature). If it is less than 50 degrees, it doesn't necessarily mean there aren't many stripers around; it just means they are not ready to burn the calories needed to feed. The colder the water, the less a fish has to eat due to its slower metabolism at those depths. As soon as the temperature hits 55 degrees, the feed bag should be on, and all the dormant stripers immediately turn the feed bag on hard! I also notice that afternoons fish better than mornings early in the spring. I’ll explain why in the next blog. As a side note, I believe the bigger fish are so dialed into the herring migration they follow them right up to the Lawrence Dam and jet past our typical schoolie areas so quickly they are near impossible to target despite the water temperature.
This photo is from May 12th, 2019. It was the first day of good numbers. The temperature was finally over 50 degrees (52.6). The fish were not active on top and not actively feeding below. But, we did very well by getting down to them with savage sand eels this day.
So now you have a basic understanding of the environmental factors of how stripers migrate up the coast. Migration movements are triggered by natural events such as extended daylight periods and moon cycles to gather up and start their journey. The prevalent weather can dictate which route they comfortably take to their pre-programmed "home." As they get closer to their summer resting spots, they may make it earlier than you'd expect. Still, to catch them in any numbers, you should be looking for water above 50 degrees, particularly on days with wind out of the southernly directions. I have no doubt we have the first wave of fish in the area any day now, but things will explode if we have some consistent weather rolling in. (So far, April has been super cold and has constant northern winds. That needs to change over the next two weeks to accelerate our striper bite.)
We will start hearing reports of local anglers both from shore and the boat about some fish showing up. They may be holdovers, early arrivals, or just plain hungry. Usually, you will hear of people catching a few here and a couple there, but then it just busts wide open one day out of nowhere. Using this information, I will predict the first day of solid striper fishing (20+ fish in an outing)! So, my prediction for the first push of fish in the Merrimack will be on Friday, May 13th, in the afternoon. Book it!
In the next part of this series, we will focus on herring migration and how it affects your fishing tendencies of where and how to fish once the stripers begin to move it. What features to look for when choosing a fishing spot, and what are the best/worst conditions for schoolie fishing. In the final part of this series, we will cover the rods, reels, setups, etc. I feel it is essential to learn how and why we fish, then use some backward design to get the best appropriate gear!