Marine fish invasions at the Isthmus of Panama

Latest update May 10, 2019 Started on July 1, 2018

I am developing a project aimed at investigating exotic fish species at both sides of the Isthmus of Panama. The Panama Canal facilitates ship traffic but also the passage of exotic fish species accross Caribbean and Pacific coasts

July 1, 2018
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The first review on the Atlantic Tarpon in the East Pacific is out!

We just got our first contribution on the history of Atlantic Tarpon presence in the Eastern Pacific published in the journal "Reviews in Fish Biology and Fisheries"

You can read the article on-line here: (

In The Field

Visiting the Miraflores Locks

To have a better feeling of what is involved when crossing the Panama Canal, I decided to visit the Miraflores Locks. This lock system lifts (or lowers) ships intending to reach the Gatun Lake (or to enter the Pacific Ocean).

The reason to visit this place is because many of the early assessments on exotic fish species made in the 70s and 2000s have been done in the locks when these have been dewatered for maintenance. Other assessments have been done in the adjacent areas of the locks like the Miraflores Lake or the Spillway near the locks.

With support from the Smithsonian Tropical Research Institute, we may be able to sample the locks in the second semeters of 2019. I will be posting then details of this activity which will likely provide hints into what is happening at the moment with the marine fish species entering the Gatun Lake.

This video shows in a nice way what is involved when entering these locks.

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Marine fish entering the Gatun Lake?

The man-made and freshwater [Gatun Lake] ( has allowed ship transit at he Panama Canal for more than 100 y. This lake has also somehow prevented that many marine and brackish species cross from the Caribbean to the Pacific or viceversa.

Nevertheless a handful species that are tolerant to freshwater have been able to cross the Lake Gatun colonizing new envirnments and becoming exotic in the Pacific or Caribbean coasts.

In April and July of 2019, with support from scientists from the [Smithsonian Tropical Research Institute] (,,) I will be visiting the Gatun Lake to investigate the state-of-the-art on marine fish colonization in this lake. I will be using a lot of traditional knowledge from fishers in the lake, but also sampling with conventional fishing methods (e.g. gillnets) to get an overview of the number of marine fishes that are now present in the lake.

Some of the standard methods may not be sufficient to sample or identify fishes in many areas around the Gatun Lake. For example, deep areas or simply areas where diving or snorkeling is not possible. New technologies hold promise to help us get a complete overview on this issue.

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In The Field

Looking for Tarpon babies at Punta Chame

Most Tarpon that are observed in the Eastern Pacific are large individuals. Since they can live up to 80 years and are a highly migratory species, those large individuals could be migrants from the Caribbean that have crossed the Panama Canal.

We were interested in knowing whether small Tarpon are found in the Pacific coast of Panama. This could give us an indication of whether reproduction of this exotic species is already taking place in the Eastern Pacific.

From what is known about the nursery habitats of Tarpon in the Atlantic, we were looking for mangrove areas, where brackish and temporary lagoons are found. This took us to [Punta Chame] (, where some fishers indicated the existence of a lagoon of this type, the prefered habitat of baby Tarpon.

We stayed for a weekend at Punta Chame, talking to artisanal fishers about Tarpon and visiting mangrove sites where baby Tarpon could be found. Fishers identified the lagoon and the presence of small Tarpon in the area. Unfortunately, the lagoon dissapered a few years ago (in 2009) after a combination of strong tides and erosion that broke one of of its walls.

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The Atlantic Tarpon is a migratory fish highly prized by recreational fishers in its native range. This fish is one of the few fish that has been able to cross the Panama Canal being now relatively common in areas of the Pacific coasts of Panama, Costa Rica and Colombia. Very little is known about how this species is performing in the ecosystems of the Pacific after it was first observed about 80 years ago.

In the last years, we have been visiting fishing villagers of Colombia, Panama and Costa Rica in search of evidence of the presence of Tarpon. We have talked to small-scale fishers but also to recreational fishers. Slowly we are re-constructing what we know about Tarpon in their recently colonized new environment: the tropical eastern Pacific.


Large Tarpon at the Gulf of San Miguel

The Gulf of San Miguel in the Pacific coast of Panama is a relatively isolated area in the Darién province of this country. Relatively well preserved mangroves thrive in several parts of the Gulf and small-scale fishing activities are an important part of the economy of people there.

We visited [La Palma] (,Dari%C3%A9n)) because several people pointed to us that large Tarpon were relatively common along the Tuira River, the largest River of Panama. We had various interviews with fishers that corroborated the information about Tarpon and visited various fishing villages in search for some more evidence.

Due in part to its isolation the Gulf of San Miguel still contains relatively well preserved coastal ecosystems and seems to be an area where adult Tarpons have found a suitable habitat in the Eastern Pacific

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Expedition Background

Invasive species can pose a threat to marine and terrestrial ecosystems. In the ocean, maritime canals have historically been involved in the introduction of species to new environments (seas where species were not previously present). The Panama Canal has greatly benefit world ship traffic for more than 100 years but also has been involved in the introduction of exotic species into either the Pacific or the Caribbean coasts of Panama.

In the last years with a group of scientists I have been involved in documenting the range expansion of the Atlantic Tarpon in the Pacific of Costa Rica, Panama and Colombia. This highly migratory species is one of the fish that has been able to succesfully cross the Panama Canal. As the Panama Canal has been recently expanded, the likelhood of more fish passing from either the Pacific or the Caribbean may have increased. In the following years I will be investigating the extent of fish invasions across the Panama Canal in order to elucidate the potential effects that these invasions may have on their new environments.


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