Three heavyweights in Ocean Conservation - Monterey Bay Aquarium, Blue Oceans Institute, and Environmental Defense Fund - have joined forces to come to the aid of sushi lovers with sustainable seafood guides.

It's a good move considering that bluefin tuna is one of the most prized sushi delicacies but amounts to eating an endangered species.

Given that reality and confusion about other overfished species, a sushi lover with a conscience may be inclined to give in and order the gyoza, edamame, and chicken teriyaki and call it a night. But let's face it, that's not why you went out to eat.

Well, no longer! The guides, which will be officially launched on October 22, make the point that there are a lot of sustainable seafood options. In tuna alone, it gives a cautious "good alternative" to bigeye and yellowfin tuna if troll or pole caught. But if the fish are caught on a longline (that ensnares sea turtles and other bycatch) it's listed under the "avoid" category.

Here's a "green" list of "best choices" from the Monterey Bay Aquarium's Seafood Watch sushi guide:

Aji/Sawara/Spanish mackerel*
Amaebi/Spot prawn (BC)
Awabi/Abalone (US farmed)
Gindara/Sablefish/Black cod (AK+, BC)
Hirame/Pacific halibut+
Hotate/Bay scallops (farmed)
Ikura/Salmon roe (AK wild)+
Iwana/Arctic char (farmed)
Iwashi/Sardine (US)
Izumidai/Tilapia (US farmed)
Kaki/Oysters (farmed)
Kanikama/Surimi/Imitation crab
(AK pollock+)
Katsuo/Bonito/Skipjack tuna
(troll/pole)
Masago/Smelt roe (Iceland)
Mirugai/Giant clam/Geoduck (wild)
Murugai/Mussels (farmed)
Sake/Salmon (AK wild)+
Shiro Maguro/Albacore tuna (troll/pole, BC or US+)
Suzuki/Striped bass (farmed or wild*)
Uni/Sea urchin roe (Canada)

Here's the list of good alternatives:

Now here's the "red" avoid list:

Looking at this list, I'd say it's a good start. But the impetus should really fall to the chef or restaurant so you don't have to ask whether the uni is from Maine, California or Canada. But come to think of it, I usually ask chefs where the fish is from -- and they are inclined to tell you if you're interested. At least, that's been my experience.