Originally introduced to Hawaii for food in 1956, it’s ironic that most people haven’t eaten a Tahitian Prawn (Macrobrachium lar) before. No, these are not the crustaceans you get from the North Shore Shrimp Trucks. The vendors more commonly sell either penaeid “white shrimp (which are marine), and less commonly, a freshwater palaemonid “Giant River Prawn” (M. rosenburgii) that is supposed to have slightly more tail meat than its Tahitian congener.

Although not as common on Oahu, there are a number of people that catch them on the outer islands by using baited traps, Hawaiian sling (3-prong), and hand nets. I prefer to perform the latter of the 3 at night, where I use either a bright headlamp or dive light to scare them into my net… because catching dinner is half the fun!!!

Packing only a high-lumen headlamp (~200 lumens), reef-walking tabis (Hanapaa cleated, felt tabis), a < 12" mouth handnet and a mesh bag (to hold the catch), I usually catch 40-50 individuals in about 90 minutes.
Like most arthropods (with compound eyes), the prawns eyes reflect light well and are easy to spot, even in agitated water.

However, they are much easier to catch in calm, shallow water like this one here.

The trick is to place the net in the water downstream of the prawn (holding it upstream will cause it to fold over on itself), and use another object to misdirect it into the net.

Here, I use my extended tripod, since it was too tedious to keep folding up and putting it away to take photos anyway. I would usually either use my hand, or a short stick from the stream bank, if I wasn’t trying to photo document this activity.

Because they are not able to see well at night, the prawns are easily blinded by the ridiculously bright light… Although, they do feel the aberrant vibrations from my feet and whatever crutch I’m messing around with. It doesn’t ALWAYS work, but it works FAR SUPERIOR than trying to swat away at a prawn… which is pretty much an epic fail.

They are programmed to dart away from any disturbance, the larger the disturbance, the larger the reaction… especially when vision is not available. This same method can work during the day, but not as well for obvious reasons. The reflection from daylight off of the water’s surface makes it more difficult as well.

Since they stay alive much longer than if I had speared them, the prawns end up being pretty fresh, up until grilling. Here, I douse the symmetrically halved individuals with some truffle and olive oil, as well as several types of seasonings.

A short time later, they are thrown on some hot coals, where they are grilled til bright orange. Extremely fun activity wrangling them, but it is just as much of an event getting to cook and eat them right off the grill as well!

NOTE: Tahitian prawns are obviously not native to Hawaii, and I have no problem with people who take more than their share of these guys out of freshwater streams. Like the native freshwater fish and macroinvertebrates in Hawaii, they have an amphidromous life-history, where the ocean is required to complete their life cycle. The eggs are brooded for a short time until the larvae hatch and taken downstream, where they will disperse and return to freshwater streams on the same or on different islands. Therefore, they are ubiquitous throughout the Hawaiian Islands and actively compete with native stream organisms for resources. “Prawn” away folks, but be careful not to take the small ones… they are difficult to distinguish apart from the native prawn (Macrobrachium grandimanus – Opae oehaa), or even native shrimp (Atyoida bisulcata – Opae kala ole); shown on left and right, respectively:

Regardless of size, Opae oehaa has ~15 dorsal teeth (spines) on its rostrum (spine sticking out of nose), while the Tahitian prawn should have less than ~10. Opae kala ole has no dorsal teeth on its rostrum… unless that counts as one? haha. The mottling on both natives is obvious, whereas the introduced species doesn’t typically have any color patterns along it’s body.

Oh and another thing, if catching Tahitian prawns to eat, you probably want to collect them from “cleaner” streams, away from residential areas and businesses. For instance, I usually only eat the ones I catch in remote streams on Kauai, Maui and Hawaii Island (Big Island)… but that doesn’t mean there’s no prawns on Oahu (etc) that are clean to eat. Happy hunting and watch out for the native fish and macroinverts!

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Aloha and mahalo nui for visiting… Come back again soon!