Co-occurring barracuda species, the reason that I went to Papua New Guinea in the first place — I encountered the same five species in both the Madang area and in Kimbe Bay, including the great barracuda, subject of my previous research.
A large great barracuda (Sphyraena barracuda) blending in extremely well with the background over sand around an island. Visibility was lower than at more distant sites — indeed, it was lower over this patch of sand than in other microhabitats around the island — that further augmented the barracuda's neutral-gray camouflage. (Restorf Island, Kimbe Bay)
Pickhandle barracuda (S. jello). I encountered four barracuda species at this site, an offshore seamount that rises from about 600 m to top off at about 4 m. The seamount was always a particularly spectacular and interesting dive site, often characterized by vicious and rapidly-changing currents (sideways, up, and down within a few minutes' span). (Planet Rock, Madang)
A close view of part of a small school of pickhandle barracuda, hanging out at the upcurrent end of a high-current pass in the barrier reef. (Magic Passage, Madang)
Part of the school of pickhandles that I often saw at or near a pass in the barrier reef. (Milinat Pass, Madang)
A school of pickhandle barracuda deep on the barrier reef — they'd typically travel up and down over about a 50- to 60-m vertical range as they milled about on the reef's steep slope. The interesting thing about this view of the school is that some — one is particularly so — have developed vertical bars across their backs as they paused in this deep gully. These bars are very similar to those that appear in the pickhandle's closest relative, the great barracuda.
Bigeye barracuda (S. forsteri)...the species we encountered frequently that wasn't 'supposed' to be where we were. Unauthorized yellow fins, not mentioned in the ID books, made their identification a bit problematic, though the black spot at the base of their pectoral fins (and the relatively large eyes that give them their name, though they're also known as blackspot barracuda) is a bit of a giveaway (Milinat Pass, Madang).
A school of bigeye barracuda executes a nice curving turn in front of a pass in the barrier reef. (Milinat Pass, Madang)
Clif Haugen, my research assistant on this trip, in hot pursuit of a school of bigeye barracuda near a pass in the barrier reef. (Milinat Pass, Madang)
A school of bigeye barracuda about to swim downcurrent through a pass in the reef. (Milinat Pass, Madang)
Bigeye barracuda coming through the pass toward the open sea and a haplosclerid barrel sponge situated where the reef's slope begins to steepen. (Milinat Pass, Madang)
A closer view of bigeye barracuda, schooling in front of the passage at Milinat (Milinat Pass, Madang).
A school of bigeye barracuda seems to be reliably resident quite deep on this seamount's spur that slopes to very deep water. Larger blackfin barracuda (S. qenie) were also a fixture on the reef but tended to roam further from the reef — vertically and horizontally. I once had this group swim very close beside me as I headed down the spur — I enjoyed the company but they abruptly left when I reached about 50 m depth, where I saw a sizeable and very active gray reef shark (Carcharhinus amblyrhynchos). I was right behind the barracuda as they headed upslope — perhaps it was the absorbed nitrogen that made me expect loyalty from a barracuda. (Joelle, Kimbe Bay)
The yellowtail barracuda (S. flavicauda) is one of the smaller species and the smallest that I've seen in PNG. These barracuda generally act pretty much like a stereotypical 'prey' animal — they even hide in staghorn coral thickets alongside smaller damselfishes and cardinalfishes — and are hardly the kind of top predators that the word barracuda generally brings to most people's minds. These delicately-built barracuda are fascinating to watch and I believe that I may yet learn a good deal about barracuda social evolution by spending more time with these fish and comparing their behavior with their larger relatives. One group that I did spend a lot of time observing — shown here — had its home centered on a sprawling coral formation not far from the northern tip of a barrier reef island, on the lagoonal side of the reef, just across the shallow reef crest from the deep ocean's pounding surf. (Pig Island, Madang)