In the absence of sea shells

Observation by Mike Brubaker: I have been watching the same stretch of beach now for 25 years. It is the north side of McDonald Spit, located between Seldovia and Homer. I remember in the early 2000s walking the beach with toddlers, buckets in hand, and the fun of looking for unusual shells that we could bring home and turn into an art project. There were all kinds, in addition to the clam shells and cockles, there were blue mussels, tridents and all kinds of snails, scallops, pacific oysters, sand dollars. Yesterday I walked the entire 3 mile loop of the Spit and did not see a single shell. There were pieces of old shells but nothing along that water line that was new. Or to speak of above tide line. What happened? This is not an area that is under pressure from over zealous collectors. I am guessing that this has to do with a more gradual decline in marine life in the intertidal zone of this area. I feel like I have seen this gradual decline over years. I am hoping that our friends at the Kasitsna Bay Laboratory or the Alaska Sea Life Center can advise on this observation.

Comment by Kris Holderied:

It's interesting that you saw such a large change along McDonald Spit. I've also found that beach to have many seashore treasures, but I haven't walked out there in the last few years. I agree with you that I wouldn't expect a lot of shell collecting from that area. Do you think it was a relatively sudden change in the shells this year, a decline over time or a bit of both? If it's been a sudden change, one thing I'd wonder about is ice scour, since there was so much ice on both sides of Kachemak Bay this winter. Strong winter wind and wave patterns might have also have caused sand movement and sedimentation to change the beach and move things around - did you notice a change in the slope or shape of the beach? It will be interesting to see if more shells show up this summer and how the shape of the beach changes with summer ocean patterns. Thanks for the observation!

AI Comment from GPT 5:

This post describes a striking shift on the north side of McDonald Spit: after decades of finding diverse, fresh shells along the 3-mile beach, a recent walk turned up none, suggesting a possible long-term decline in intertidal shell-bearing life, with questions about whether winter ice, waves, or sediment changes played a role this year. Prior local notes in Kachemak Bay have documented sharp intertidal changes—especially sea star losses—with some patchy rebounds at depth and in certain nearshore spots.

Related posts offer context for both rapid physical reshaping of beaches and longer-term biological stressors that could influence what washes ashore. Physical processes can reorganize or concentrate shell material without implying population loss, as seen in the unusual shell grid formation on Haida Gwaii where tides and waves were suspected to arrange shell fragments in patterns rather than remove them entirely (Mystery lines on Haida Gwaii beach). Episodic events also matter locally: a single winter storm once stranded and killed thousands of razor clams on Cook Inlet beaches, abruptly changing what people found on the tide line (Shell shock - thousands of Ninilchik clams wash up on beach in unusual die-off). At the same time, several posts point to ecological shifts that can reduce or alter shell-forming invertebrates. Sea star wasting led to major intertidal changes around Seldovia and Homer, with low counts persisting in many sites and some movement of survivors to deeper water, indicating broader community disruption in recent years (Sea star populations in Kachemak Bay annihilated by wasting disease; No Sea Stars on Bishop's Beach; Low Tide and No Sea Stars). Broader ocean chemistry changes have been linked to shell condition in other regions, including damage to young Dungeness crab shells in the Pacific Northwest and accelerated acidification off California inferred from thinning foraminifera shells, which together highlight mechanisms that can affect calcifiers and, ultimately, what shells are available to wash ashore (Seawatch: Ocean acidification affecting crab shells; Tiny shells reveal waters off California are acidifying twice as fast as the global ocean). Regional ecosystem shifts detected in Alaskan seafloor shell assemblages further suggest community change over recent decades, consistent with the long-term decline the post describes (Alaskan seashells reveal a changing Arctic). Considering these threads, both recent winter ice and wave dynamics and multi-year biological changes could influence the present absence of fresh shells along McDonald Spit, and tracking summer beach shape and shell return—as suggested—may help distinguish between them.