HIFWGv1

A Fishwatcher's Guide to the Marine Invertebrates of Hawai'i

Part 1 of 4, To: Part 2, Part 3, Part 4,

Bob Fenner

Other reasons to visit: Beautiful lava formations

Due to it's geographical placement, the principal islands of Hawai'i find themselves treated as a distinct sub-faunal region of the Indo-Pacific. Ocean currents and distances from other shallow water areas have conspired to produce a large proportion of endemic near-shore marines. Indeed Hawai'i vies with the Sea of Cortez of Mexico's eastern Pacific coast, and the Red Sea for percentage of endemic fish species, with about a quarter found only there.

And what an abundance for Fishwatcher's and aquarists! More than a hundred fishes (and a few invertebrates) are collected for our interest from Hawai'i's principal islands. Some you know well, like the Yellow Tang, Zebrasoma flavescens, others ought to be more utilized in our interest like the beautiful, hardy and abundant Milletseed Butterflyfish, Chaetodon miliaris. How many species of wrasses, moray eels and butterflyfishes can you find here? Some forty three, thirty eight and twenty four species respectively!

There are many dive and snorkeling spots to explore, where you can glimpse this vast fauna up close one on one, and a few nice public aquariums with interpretive displays. Add to that the fact that America's 50th state has excellent year round weather, air flight services, and accommodations, and it's hard to find a better place to visit to investigate the aquatic world.

Here is my account of the species of tropical fishes utilized in the hobby and trade of aquarium keeping that hail from Hawai'i and their scored survivability. Also listing some that should be left out, others that ought to be added and brief notes on their, range, feeding habits, ecotype, and other pertinent husbandry tidbits. My intent is obvious. To encourage you to witness the living world firsthand, to inform "all the players" especially collectors and "end-user" consumers (hobbyists) of the best livestock available, and reciprocally to discourage use of inappropriate species.

Ecotype Statements

I've offered some broad strokes here in describing very generally where the various fish groups and species are typically found. Other authors have been much more specific in defining reef geographies and particular niches, but I'll assure you that duplicating biotopes is not essential. Indeed, almost all hobbyist arrangements are a mish-mash of mixed species that would never meet in the wild, and most get along just fine.

On the other hand, I cannot encourage you enough to go beyond the simple statements offered here in investigating and doing your best to mimic a physical and biological slice of the ocean (or any part of the "real" world you'd like to recreate in miniature). The printed works listed here, Internet, and actual travel to the area are the best means of gaining knowledge of what makes up a given habitat, living and physical.

Captive Suitability Scoring:

After long thought, investigation of others declared opinions, and handling tens of thousands of these species I've come to a set of "scores" for each on its likelihood of surviving the rigors of aquarium care. Yes, to some degree this information is necessarily historical (what has happened, may not be the general trend to come), and is subject to "improvement" on the keepers side as a consequence of providing larger, more stable quarters (like public aquariums), and more diligent husbandry. But, by and large a relative score of one (1) indicates the "highest and best" survivability under captive conditions; let's say most of the specimens of this species collected surviving more than three months. A score of two (2) is indicative of mortality of more than fifty percent between one and three months. Lastly, and sufficient for our purposes, a three (3) is the worst score, with more than 50% of the species perishing before a months time of capture. I entreat you to leave the latter group to the sea, or at least to study about their care ardently and provide the best possible circumstances for these animals.

Non-Fish Underwater Life of Hawai'i

Algae: Macro Brown, Red, Green... (ref.: ReefWatcher's Field Guide to Alien and Native Hawaiian Marine Algae

Caulerpa racemosa, Green Grape Algae. At right in Hawai'i.

Galaxaura sp. (maybe G. marginata, see: Galaxaura species in Hawaii) At right in Hawai'i and below, a bleached-out colony in the Red Sea, and a small piece off Cozumel. Distinct dichotomously branching species of pink to red color.

Halimeda sp., Money or Cactus Algae for its circular, coin-like segments. One of twenty five or so marine species of this coralline (yes, though not a Red or encrusting) Green Algae can be found in sparse patches (H. incressata occasionally occurs as a dominant species). Here on the Big Island. In places a considerable contributor to sand make-up... look close at the white small chunks on the beach.

Padina sp., Scroll Algae, a calcium carbonate encrusting Brown Algae in the wild or marine aquariums. This is Padina jamaicensis in Belize.

Peyssonnelia sp. An encrusting Red. Class Rhodophyceae, Subclass Florideophycidae, Order Gigartinales, Family Peyssonneliaceae. Below, in an aquarium, Cozumel and the Red Sea.

Turbinaria ornata. Kona, Hawai'i pix.

Ulva, Sea Lettuce, this and related Enteromorpha are great fish foods.

Sponges:

Leiodermatium sp. Wavy Cave Sponge. Hard to the touch and distinctive in shape. Found in caves, within crevices. May be endemic to Hawai'i. Kona pix.

Phorbas sp. Red Phorbas Sponge. Densely covered with pores and excurrent openings. Encrusts dead and live corals. Kona pix.

Spirastrella (Sphenciospongia) vagabunda Ridley 1884, the Vagabond Boring Sponge. Bores its way into carbonate places (rock, corals...) by acidic secretion. An important group of organisms for "recycling" limestone. Hawai'i photos.

Strongylphora sp., Amorphous Cave Sponge. Creamy though hard to the touch, fuzzy finger-like appearance. Found deep in caves and lava tubes (Pukas), covering walls at times. Kona pix.

Stylinos sp., Orange Stylinos Sponge. Rough cellulose appearance. Soft material that is easily torn, but don't touch. This sponge will stain and irritate skin. Only a few inches across. Kona pix.

Suberites sp., Blue Suberites Sponge. Intensely blue, as thin sheets. Occurs in high surge areas. Colonies in crevices are a few inches across. Kona pix.

To: Part 2, Part 3, Part 4,

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